Clinical Approach to Palpitations

Pediatric Comprehensive Framework

1
Symptom Overview
Overview
2
Pathophysiology
Mechanism
3
History Taking
History
4
Physical Examination
Examination
5
Differential Diagnosis
Differential
6
Investigations
Workup
7
Clinical Decision-Making
Algorithm
8
Pearls and Pitfalls
Summary

1. Symptom Overview

Understanding the clinical significance and classification of palpitations in pediatric patients

Palpitations represent the subjective awareness of one’s own heartbeat and are a common presenting complaint in pediatric cardiology clinics, accounting for approximately 10-15% of referrals. While less commonly reported than in adults due to younger children’s difficulty articulating symptoms, the prevalence of palpitations increases significantly during adolescence, with studies suggesting up to 16% of adolescents experience palpitations at some point. Importantly, the vast majority of pediatric palpitations (approximately 85-90%) are benign, but identifying the minority with serious underlying pathology is critical.

Definition

Palpitations are defined as an unpleasant awareness of the heartbeat, often described by children and adolescents as the heart “racing,” “pounding,” “fluttering,” “skipping,” or “beating hard.” In younger children, equivalent complaints may include chest discomfort, feeling their heart “jumping,” or nonspecific complaints of not feeling well. The symptom reflects perceived abnormalities in heart rate, rhythm, or contractility.

Key Epidemiology

10-15% of pediatric cardiology referrals
Up to 16% of adolescents report palpitations
85-90% are benign in origin

1-2% have significant arrhythmia
Peak incidence during adolescence
Female predominance in adolescents (2:1)

Classification by Duration and Pattern

Pattern	Duration	Common Causes	Clinical Significance
Brief/Isolated	Seconds (single beats or brief runs)	Premature atrial contractions, premature ventricular contractions, sinus arrhythmia	Usually benign; very common in healthy children
Paroxysmal	Minutes to hours with abrupt onset and termination	Supraventricular tachycardia, Wolff-Parkinson-White syndrome, atrial flutter	May indicate accessory pathway or re-entrant circuit; requires evaluation
Sustained	Hours to continuous	Sinus tachycardia, automatic atrial tachycardia, permanent junctional reciprocating tachycardia	Prolonged tachycardia may cause tachycardia-induced cardiomyopathy
Chronic/Recurrent	Frequent episodes over weeks to months	Anxiety, inappropriate sinus tachycardia, postural orthostatic tachycardia syndrome	Significant impact on quality of life; often requires comprehensive evaluation

Classification by Character

Regular Palpitations

Description: Patient perceives a regular, fast rhythm without skipping

Suggests: Sinus tachycardia, supraventricular tachycardia, ventricular tachycardia

Key question: “Does your heart beat fast but steady, like a drum?”

Irregular Palpitations

Description: Patient perceives skipped beats, extra beats, or chaotic rhythm

Suggests: Premature atrial or ventricular contractions, atrial fibrillation (rare in children)

Key question: “Does it feel like your heart skips or does an extra beat?”

Classification by Onset and Termination

Characteristic	Description	Suggests
Abrupt onset and termination	“Like a light switch” — sudden start and stop	Paroxysmal supraventricular tachycardia, Wolff-Parkinson-White syndrome, re-entrant tachycardia
Gradual onset and termination	“Builds up and winds down” over seconds to minutes	Sinus tachycardia (physiologic or anxiety-related), automatic atrial tachycardia
Exercise-related onset	Occurs during or shortly after physical activity	Physiologic sinus tachycardia, catecholaminergic polymorphic ventricular tachycardia, long QT syndrome
Position-related onset	Occurs with standing or position change	Postural orthostatic tachycardia syndrome, orthostatic hypotension with compensatory tachycardia
Emotion/stress-related	Occurs during anxiety, excitement, or fear	Physiologic response, anxiety disorder, panic attacks, catecholaminergic polymorphic ventricular tachycardia

Age-Specific Considerations

Age Group	Presentation Characteristics	Common Causes	Special Considerations
Infants (0-1 year)	Cannot verbalize; presents with irritability, poor feeding, pallor, or lethargy during episodes	Supraventricular tachycardia (most common arrhythmia), congenital heart disease, accessory pathways	SVT in infants may present as heart failure if prolonged; high index of suspicion needed
Toddlers (1-3 years)	May point to chest, appear frightened, or say “heart hurts”	Supraventricular tachycardia, premature beats, viral myocarditis	May be able to tap out rhythm; parental observation crucial
School-age (4-11 years)	Can describe sensations; may use terms like “racing” or “pounding”	Sinus tachycardia, premature atrial contractions, supraventricular tachycardia, anxiety	Often related to exercise or emotions; screen for anxiety and school stress
Adolescents (12-18 years)	Adult-like descriptions; may minimize or exaggerate symptoms	Anxiety, postural orthostatic tachycardia syndrome, caffeine/stimulants, premature beats, supraventricular tachycardia	Screen for substance use (caffeine, energy drinks, drugs); anxiety very common; female predominance

Key Concept — The Pediatric Palpitations Paradigm:

In children and adolescents with palpitations, the differential can be organized into four main categories:

Benign/Physiologic: Sinus tachycardia, sinus arrhythmia, premature beats (approximately 85%)
Supraventricular arrhythmias: Supraventricular tachycardia, Wolff-Parkinson-White syndrome, atrial flutter (approximately 10%)
Ventricular arrhythmias: Ventricular tachycardia, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia (approximately 2-3%)
Non-cardiac: Anxiety, postural orthostatic tachycardia syndrome, thyroid disease, anemia, medications/substances (approximately 2-3%)

Impact on Quality of Life

Palpitations, even when benign, can significantly impact a child’s quality of life and that of their family. Frequent episodes may lead to:

School absenteeism and decreased academic performance
Restriction from sports and physical activities (often self-imposed or parental)
Anxiety about heart health, which may perpetuate symptoms
Sleep disturbances if episodes occur at night
Parental anxiety and frequent emergency department visits

Clinical Pearl — Documenting the Rhythm

Encourage families to have the child “tap out” the rhythm during episodes, or record a video of the child tapping their chest or showing their pulse at the neck. Many smartphone apps and smartwatches can also record heart rate or single-lead ECG during symptoms, providing invaluable diagnostic information. A captured rhythm during symptoms is worth more than multiple normal ECGs.

2. Pathophysiology and Mechanisms

Understanding the underlying mechanisms of palpitations in pediatric patients

The perception of palpitations results from the brain’s awareness of cardiac activity that is normally unnoticed. This awareness can occur when there are actual changes in heart rate, rhythm, or contractility, or when there is heightened sensitivity to normal cardiac activity. Understanding the mechanisms of cardiac rhythm generation and the pathophysiology of arrhythmias is essential for evaluating pediatric palpitations.

Normal Cardiac Conduction System

Component	Structure	Function	Intrinsic Rate
Sinoatrial Node	Located at junction of superior vena cava and right atrium	Primary pacemaker; initiates electrical impulse	60-100 bpm in adults; higher in children (age-dependent)
Internodal Pathways	Three pathways through right atrium	Conduct impulse from sinoatrial node to atrioventricular node	Not applicable (conduction tissue)
Atrioventricular Node	Located in interatrial septum near coronary sinus	Delays impulse to allow atrial contraction; backup pacemaker	40-60 bpm
Bundle of His	Penetrates central fibrous body	Conducts impulse from atrioventricular node to ventricles	40-60 bpm
Bundle Branches	Right and left branches along interventricular septum	Rapidly conduct impulse to respective ventricles	20-40 bpm
Purkinje Fibers	Terminal network throughout ventricular myocardium	Distribute impulse to ventricular muscle cells	20-40 bpm

Mechanisms of Arrhythmia Generation

Arrhythmias causing palpitations arise through three fundamental mechanisms:

Abnormal Automaticity

Mechanism: Ectopic pacemaker cells develop spontaneous depolarization faster than the sinoatrial node

Characteristics: Gradual onset; “warm-up” phenomenon; rate may vary

Examples in children: Automatic atrial tachycardia, junctional ectopic tachycardia, some forms of ventricular tachycardia

Clinical relevance: Often incessant; may be difficult to treat; can cause tachycardia-induced cardiomyopathy

Re-entry

Mechanism: Electrical impulse travels in a circuit, re-exciting tissue repeatedly

Requirements: Two pathways with different conduction velocities, unidirectional block in one pathway, slow conduction in the other

Examples in children: Atrioventricular re-entrant tachycardia (Wolff-Parkinson-White syndrome), atrioventricular nodal re-entrant tachycardia, atrial flutter, some ventricular tachycardias

Clinical relevance: Abrupt onset and termination; can often be terminated with vagal maneuvers or adenosine

Triggered Activity

Mechanism: Afterdepolarizations (early or delayed) reach threshold and trigger additional action potentials

Causes: Electrolyte abnormalities, drugs, catecholamines, ischemia

Examples in children: Long QT syndrome (early afterdepolarizations), catecholaminergic polymorphic ventricular tachycardia (delayed afterdepolarizations), digitalis toxicity

Clinical relevance: Often exercise or emotion-induced; may degenerate to life-threatening arrhythmias

Developmental Considerations in Pediatric Cardiac Electrophysiology

Age-Related Differences

The pediatric cardiac conduction system differs from adults in several important ways:

Faster intrinsic heart rates: Neonates 120-160 bpm, infants 100-150 bpm, gradually decreasing to adult values by adolescence
Shorter refractory periods: Allow faster conduction and higher maximum heart rates during supraventricular tachycardia (often greater than 250-300 bpm in infants)
Accessory pathway prevalence: Higher in infancy; many pathways lose conduction capability with age (approximately 30% of infant Wolff-Parkinson-White resolves by age 1 year)
Autonomic tone: Higher vagal tone in children contributes to sinus arrhythmia and may terminate supraventricular tachycardia more easily

Mechanisms by Specific Condition

Condition	Mechanism	Why It Causes Palpitations	Treatment Implication
Sinus tachycardia	Physiologic increase in sinoatrial node firing rate due to catecholamines, fever, pain, anxiety, or hypovolemia	Increased heart rate and contractility create awareness of heartbeat	Treat underlying cause (fever, dehydration, pain, anxiety); no antiarrhythmic needed
Premature atrial contractions	Ectopic atrial focus fires before next expected sinus beat	Compensatory pause followed by stronger contraction creates “skipped beat” sensation	Usually benign; reassurance; avoid triggers (caffeine); rarely need treatment
Premature ventricular contractions	Ectopic ventricular focus fires prematurely; followed by compensatory pause	Ineffective contraction followed by pause and forceful beat; may feel like “flip-flop”	Benign if structurally normal heart; treat if frequent (greater than 10-15%) or symptomatic
Supraventricular tachycardia (atrioventricular re-entrant tachycardia)	Re-entry circuit using accessory pathway and normal conduction system	Very rapid, regular rhythm (often 180-280 bpm) causes pounding sensation	Vagal maneuvers, adenosine for acute termination; catheter ablation for recurrent cases
Wolff-Parkinson-White syndrome	Accessory pathway (bundle of Kent) allows rapid atrioventricular conduction and re-entry	Paroxysmal rapid rates; risk of rapid ventricular response if atrial fibrillation develops	Catheter ablation recommended for symptomatic patients; risk stratification important
Atrioventricular nodal re-entrant tachycardia	Re-entry within or near atrioventricular node using dual pathways	Abrupt-onset rapid regular rhythm; may feel neck pounding (cannon A waves)	Vagal maneuvers, adenosine; catheter ablation highly effective
Long QT syndrome	Prolonged ventricular repolarization leads to early afterdepolarizations and triggered activity	May present as palpitations before progression to torsades de pointes	Beta-blockers, avoid QT-prolonging drugs; implantable cardioverter-defibrillator in high-risk patients
Catecholaminergic polymorphic ventricular tachycardia	Mutations in ryanodine receptor or calsequestrin cause abnormal calcium release during catecholamine stimulation	Exercise or emotion triggers bidirectional or polymorphic ventricular tachycardia	Beta-blockers, flecainide, implantable cardioverter-defibrillator; avoid competitive sports
Postural orthostatic tachycardia syndrome	Excessive increase in heart rate with standing due to autonomic dysfunction	Heart rate increase of 40 bpm or greater (or greater than 120 bpm) within 10 minutes of standing	Increased fluids and salt, compression stockings, exercise reconditioning; sometimes fludrocortisone or beta-blockers
Anxiety and panic disorder	Sympathetic activation increases heart rate and contractility; heightened interoception	Awareness of normal or mildly elevated heart rate; may trigger more anxiety	Reassurance, cognitive behavioral therapy, anxiolytics if severe

Neural Perception of Palpitations

Component	Location	Role in Palpitation Perception
Cardiac mechanoreceptors	Atria, ventricles, great vessels	Detect stretch from abnormal contractions or rhythm changes
Vagal afferents	Cardiac branches of vagus nerve	Transmit signals from cardiac receptors to brainstem
Sympathetic afferents	Cardiac sympathetic nerves	Transmit signals related to cardiac stress or ischemia
Nucleus tractus solitarius	Brainstem (medulla)	Integrates cardiovascular afferent information
Insular cortex	Cerebral cortex	Conscious perception of cardiac sensations (interoception)

Often Overlooked Mechanism — Heightened Interoception

Some children and adolescents have heightened awareness of normal cardiac activity (increased interoception), particularly those with anxiety disorders. These patients may perceive normal sinus rhythm or benign premature beats as distressing palpitations. This is not “imagined” — their nervous system genuinely perceives normal cardiac activity more intensely. Recognizing this mechanism is important because treatment focuses on reassurance, reducing hypervigilance, and addressing underlying anxiety rather than cardiac interventions.

Congenital Heart Disease and Palpitations

Children with congenital heart disease are at increased risk for arrhythmias due to:

Pre-operative Factors

Abnormal anatomy creating abnormal conduction tissue
Chamber dilation or hypertrophy creating substrate for arrhythmias
Associated accessory pathways (common in Ebstein anomaly, congenitally corrected transposition)
Isomerism and heterotaxy syndromes associated with conduction abnormalities

Post-operative Factors

Surgical scars creating re-entry circuits (incisional re-entrant tachycardia)
Damage to conduction system during surgery
Atrial dilation after Fontan procedure
Ventricular dysfunction creating arrhythmogenic substrate

Ion Channel Disorders (Channelopathies)

Condition	Affected Channel/Protein	Mechanism	Arrhythmia Risk
Long QT syndrome Type 1	KCNQ1 (slow potassium channel)	Prolonged repolarization, early afterdepolarizations	Torsades de pointes, especially with exercise/swimming
Long QT syndrome Type 2	KCNH2 (rapid potassium channel)	Prolonged repolarization, early afterdepolarizations	Torsades de pointes, especially with auditory stimuli or emotion
Long QT syndrome Type 3	SCN5A (sodium channel)	Persistent late sodium current prolongs action potential	Torsades de pointes, especially at rest or during sleep
Catecholaminergic polymorphic ventricular tachycardia	RYR2 (ryanodine receptor) or CASQ2 (calsequestrin)	Abnormal calcium release during adrenergic stimulation	Bidirectional or polymorphic ventricular tachycardia with exercise or emotion
Brugada syndrome	SCN5A (sodium channel) and others	Altered sodium current creates transmural dispersion of repolarization	Ventricular fibrillation, typically during rest or fever

Complications of Sustained Tachyarrhythmias

Tachycardia-Induced Cardiomyopathy

Prolonged tachycardia (especially incessant arrhythmias like automatic atrial tachycardia, permanent junctional reciprocating tachycardia, or frequent premature ventricular contractions) can cause ventricular dysfunction. This is particularly important in pediatrics because:

Children may not complain of symptoms until significant dysfunction develops
The cardiomyopathy is often reversible if the arrhythmia is controlled
Echocardiography should be performed in any child with frequent or sustained arrhythmias
Premature ventricular contraction burden greater than 10-15% may cause ventricular dysfunction

3. History Taking

A comprehensive approach to eliciting the palpitation history in pediatric patients

Red Flags — Require Urgent Evaluation

Syncope with palpitations — Suggests hemodynamically significant arrhythmia, long QT syndrome, or catecholaminergic polymorphic ventricular tachycardia
Exertional palpitations with syncope or near-syncope — High risk for sudden cardiac death; consider channelopathies and cardiomyopathies
Family history of sudden cardiac death before age 40 — Suggests inherited arrhythmia syndrome or cardiomyopathy
Known structural heart disease — Higher risk of life-threatening arrhythmias
Chest pain with palpitations — May indicate ischemia (anomalous coronary artery) or myocarditis

Heart rates greater than 250 bpm in infants or greater than 200 bpm in older children — Risk of hemodynamic compromise
Palpitations associated with seizure-like activity — May represent arrhythmic syncope with hypoxic convulsions
Prolonged episodes (greater than 30 minutes) with symptoms — Risk of tachycardia-induced cardiomyopathy
Symptoms during swimming — Highly concerning for long QT syndrome type 1
Palpitations triggered by loud noises or startle — Suggests long QT syndrome type 2

Systematic History: The “HEARTS” Approach

Use the mnemonic “HEARTS” to ensure comprehensive history taking for pediatric palpitations:

H — How does it feel? Character of palpitations (racing, pounding, skipping, fluttering); ask child to tap out the rhythm
E — Episodes: Frequency, duration, onset and termination pattern (sudden vs gradual), age at first episode
A — Associated symptoms: Syncope, presyncope, chest pain, dyspnea, diaphoresis, pallor, nausea
R — Related triggers: Exercise, emotion, position change, caffeine, sleep deprivation, illness, medications
T — Termination: How do episodes end? Spontaneous, vagal maneuvers, rest, or require medical intervention
S — Sudden death and heart history: Family history of sudden death, arrhythmias, cardiomyopathies, pacemakers/ICDs, drowning, unexplained accidents

Characterizing the Palpitations

Question Category	Specific Questions to Ask	Clinical Significance
Character	“Can you show me with your hand how your heart beats during an episode?” “Does it feel fast and regular like a drum, or irregular like it’s skipping?”	Regular rapid = supraventricular tachycardia; Irregular = premature beats or atrial fibrillation
Onset	“Does it start suddenly like a light switch, or does it build up gradually?”	Abrupt onset = re-entrant tachycardia (supraventricular tachycardia); Gradual onset = sinus tachycardia or automatic tachycardia
Termination	“How does it stop? Does it stop suddenly or slowly wind down?” “Have you tried anything that makes it stop?”	Abrupt termination = re-entrant mechanism; Response to vagal maneuvers suggests supraventricular tachycardia
Rate	“Can you tap on the table how fast your heart beats?” “Have you or your parents counted or measured your heart rate during an episode?”	Greater than 180 bpm suggests pathologic tachycardia; smartwatch data increasingly helpful
Duration	“How long do episodes last? Seconds, minutes, hours?”	Brief seconds = premature beats; Minutes to hours = sustained arrhythmia

Targeted Questions by Suspected Cause

Suspected Cause	Key Features	Ask This Question
Supraventricular tachycardia	Abrupt onset/offset, very rapid, regular rhythm, may have neck pounding	“Does it feel like someone flipped a switch on and off? Do you feel pounding in your neck during episodes?”
Premature beats (atrial or ventricular contractions)	Skipped beats, flip-flop sensation, often at rest	“Does it feel like your heart skips a beat or does a somersault? Is there a pause then a strong beat?”
Postural orthostatic tachycardia syndrome	Symptoms worse with standing, better lying down, often associated with fatigue and lightheadedness	“Do you feel worse when standing up? Do you need to sit or lie down? Do you feel dizzy or lightheaded when standing?”
Long QT syndrome	Exercise-related (especially swimming), emotion/startle-triggered, family history of sudden death	“Have you ever had palpitations or fainted while swimming? Does your heart race when you’re startled by a loud noise?”
Catecholaminergic polymorphic ventricular tachycardia	Strictly exercise or emotion-induced, may have syncope during activity	“Do palpitations only happen during exercise or when you’re very upset or excited? Have you ever fainted during sports or physical activity?”
Wolff-Parkinson-White syndrome	Paroxysmal rapid palpitations, may have pre-excitation on baseline ECG	“Has anyone ever told you that you have an abnormal ECG or an extra electrical pathway in your heart?”
Anxiety or panic disorder	Associated with worry, fear, somatic symptoms; may occur at rest or with stress	“Do you feel worried or scared during episodes? Do you have other symptoms like tingling, sweating, or feeling like you can’t breathe?”
Caffeine or stimulant-related	Temporal relationship with energy drinks, coffee, medications	“Do you drink energy drinks, coffee, or soda with caffeine? Do you take any medications for ADHD or weight loss?”
Anemia or thyroid disease	Gradual onset symptoms, other systemic features	“Have you noticed any weight changes, feeling hot or cold, or unusual fatigue? Have you had heavy menstrual periods?”

Pediatric-Specific History Components

Birth and Neonatal History

Component	Questions to Ask	Relevance to Palpitations
Prenatal history	Were there any concerns during pregnancy? Any fetal arrhythmias detected on ultrasound?	Fetal supraventricular tachycardia or heart block may persist or recur postnatally
Gestational age and birth weight	Was the baby born full-term? What was the birth weight?	Prematurity associated with higher arrhythmia risk
Neonatal course	Was there a NICU stay? Any heart problems identified at birth?	Congenital heart disease may predispose to arrhythmias
Maternal health	Does the mother have lupus or other autoimmune disease?	Maternal anti-Ro/anti-La antibodies can cause congenital heart block

Family History — Critical in Pediatric Arrhythmias

Essential Family History Questions

A detailed family history is crucial as many life-threatening arrhythmias are inherited:

Sudden cardiac death: “Has anyone in your family died suddenly or unexpectedly before age 40?”
Unexplained accidents: “Has anyone drowned, had a single-car accident, or died in their sleep unexpectedly?”
Cardiac devices: “Does anyone in the family have a pacemaker or defibrillator?”
Known conditions: “Has anyone been diagnosed with long QT syndrome, Brugada syndrome, cardiomyopathy, or Wolff-Parkinson-White?”
Seizures: “Does anyone have seizures?” (may be misdiagnosed arrhythmia)
Fainting: “Does anyone in the family have a history of fainting, especially with exercise or stress?”
Hearing loss: “Was anyone born deaf or has hearing loss?” (associated with Jervell and Lange-Nielsen syndrome — long QT variant)

Developmental and Functional History

Developmental milestones: Normal development reassuring; delays may suggest syndromic association
Exercise tolerance: Can the child keep up with peers during physical activity?
School performance: Frequent absences, difficulty concentrating (may indicate frequent episodes or anxiety)
Sports participation: What sports does the child play? Any restrictions recommended?
Impact on daily life: How are palpitations affecting the child’s activities and quality of life?

Medication and Substance History

Medications That May Cause Palpitations

Stimulants (methylphenidate, amphetamines) — Used for ADHD; increase heart rate and may cause palpitations
Beta-agonist inhalers (albuterol, salbutamol) — Can cause tachycardia and tremor
Decongestants (pseudoephedrine) — Sympathomimetic effects
QT-prolonging medications — Antibiotics (azithromycin, fluoroquinolones), antiemetics (ondansetron), antipsychotics, antihistamines
Thyroid hormone supplements — Excess dosing causes tachycardia
Antidepressants — Tricyclics can prolong QT; SSRIs may interact with other medications

Substances and Lifestyle Factors

Caffeine — Energy drinks, coffee, tea, soda, chocolate (ask specifically about energy drinks in adolescents)
Nicotine — Vaping, cigarettes, smokeless tobacco
Alcohol — Can trigger arrhythmias (holiday heart syndrome)
Illicit drugs — Cocaine, amphetamines, cannabis (increasingly common in adolescents)
Supplements and herbals — Pre-workout supplements, weight loss products, ephedra-containing products
Sleep deprivation — Common trigger in adolescents; may unmask underlying arrhythmia tendency

Review of Systems — Don’t Miss These

System	Symptoms to Screen For	Suggests
Constitutional	Fever, weight loss, fatigue, night sweats	Infection, thyroid disease, malignancy, anemia
Cardiovascular	Chest pain, dyspnea on exertion, orthopnea, edema	Structural heart disease, myocarditis, heart failure
Neurological	Syncope, seizures, headaches, vision changes	Arrhythmic syncope vs neurological cause; channelopathies
Endocrine	Heat/cold intolerance, tremor, weight changes, polyuria/polydipsia	Hyperthyroidism, pheochromocytoma, diabetes
Psychiatric	Anxiety, depression, panic symptoms, sleep disturbance	Anxiety disorder, panic disorder, somatization
Hematologic	Pallor, fatigue, dyspnea, heavy menstrual periods	Anemia (iron deficiency common in adolescent females)

Clinical Pearl — The Collateral History

In pediatric patients, always obtain history from both the child AND the caregiver. Younger children may not accurately describe symptoms, while adolescents may minimize or hide certain behaviors (substance use, anxiety). Parents often observe signs the child doesn’t notice (pallor, behavioral changes during episodes). Additionally, ask if anyone has captured a video or used a smartwatch to record heart rate during an episode — this can be invaluable diagnostic information.

4. Physical Examination

A systematic head-to-toe approach for pediatric patients with palpitations

Systematic Framework: Use the “Head to Extremities” approach for complete examination of pediatric patients presenting with palpitations. The examination aims to identify signs of structural heart disease, arrhythmia, and systemic conditions that may cause or contribute to palpitations.

General Inspection

Appearance: Well or unwell appearing; level of distress; comfortable at rest or anxious
Growth: Plot height, weight, and BMI on age-appropriate growth charts; failure to thrive may suggest chronic cardiac disease
Dysmorphic features: May suggest genetic syndrome associated with cardiac abnormalities (e.g., Marfan syndrome, Noonan syndrome, Williams syndrome)
Skin: Pallor (anemia), diaphoresis (hypoglycemia, anxiety, significant arrhythmia), café-au-lait spots (neurofibromatosis), ash-leaf spots (tuberous sclerosis with cardiac rhabdomyomas)
Respiratory effort: Tachypnea, use of accessory muscles may indicate heart failure
Behavior: Anxious appearance, hyperventilation may suggest anxiety component

Vital Signs — Age-Appropriate Normal Values

Age Group	Heart Rate (bpm)	Respiratory Rate (/min)	Systolic Blood Pressure (mmHg)	Key Points
Neonate (0-28 days)	100-160	30-60	60-90	Wide normal range; sleeping HR may be 80-90
Infant (1-12 months)	100-150	25-40	80-100	SVT typically greater than 220 bpm in this age
Toddler (1-3 years)	90-140	20-30	90-105	Sinus arrhythmia very common and normal
Preschool (3-5 years)	80-120	20-25	95-110	Child may be able to cooperate with BP measurement
School-age (6-11 years)	70-110	18-22	100-115	SVT typically greater than 180 bpm
Adolescent (12-18 years)	60-100	12-20	100-125	Approaching adult values; BP varies with height

Vital Sign Assessment Tips

Heart rate: Count for full 60 seconds if irregular; note if regular or irregular
Blood pressure: Use appropriate cuff size (bladder width 40% of arm circumference); compare to age/height-based percentiles
Orthostatic vitals: Essential if suspecting postural orthostatic tachycardia syndrome — measure HR and BP supine, then standing at 0, 3, 5, and 10 minutes
Oxygen saturation: Should be greater than 95% on room air; desaturation may indicate structural heart disease
Temperature: Fever causes sinus tachycardia (HR increases approximately 10 bpm per 1°C above normal)

Orthostatic Vital Signs — Evaluating for Postural Orthostatic Tachycardia Syndrome

Position/Time	What to Measure	Diagnostic Criteria for POTS (Ages 12-19)
Supine (after 5 minutes rest)	Heart rate and blood pressure	Baseline values
Immediately upon standing	Heart rate and blood pressure	Note initial changes
Standing at 3 minutes	Heart rate and blood pressure	HR increase ≥40 bpm from supine OR HR ≥120 bpm
Standing at 5 minutes	Heart rate and blood pressure	Sustained HR elevation without orthostatic hypotension (BP drop less than 20/10 mmHg)
Standing at 10 minutes	Heart rate, blood pressure, symptoms	Symptoms of orthostatic intolerance (lightheadedness, palpitations, fatigue)

Head, Eyes, Ears, Nose, and Throat Examination

Eyes

Conjunctival pallor — anemia
Proptosis, lid lag — hyperthyroidism
Lens dislocation — Marfan syndrome
Jaundice — hepatic congestion (heart failure)

Oropharynx

High arched palate — Marfan syndrome
Dental erosions — gastroesophageal reflux (may coexist with anxiety)
Mucous membrane color — pallor suggests anemia
Thyroid gland — goiter, nodules (assess from front and side)

Neck Examination

Jugular venous pressure: Elevated JVP suggests heart failure; cannon A waves during episodes suggest atrioventricular dissociation (supraventricular tachycardia with retrograde atrial activation)
Carotid pulse: Assess volume and character; bounding pulse in aortic regurgitation, weak in heart failure
Thyroid: Enlargement, nodules, tenderness; thyroid bruit suggests hyperthyroidism
Lymphadenopathy: May suggest infection (associated with myocarditis)

Cardiovascular Examination

Inspection

Precordial bulge: May indicate cardiomegaly (chronic volume overload)
Visible pulsations: Hyperdynamic precordium in high-output states
Scars: Previous cardiac surgery (sternotomy, thoracotomy)
Pacemaker or implantable cardioverter-defibrillator pocket: Usually left infraclavicular area

Palpation

Apex beat: Location (should be at 4th-5th intercostal space, midclavicular line in older children); displaced apex suggests cardiomegaly
Character of apex: Hyperdynamic (volume overload), sustained/heaving (pressure overload)
Thrills: Palpable murmur indicates grade 4/6 or greater — significant structural abnormality
Right ventricular heave: Parasternal lift suggests right ventricular hypertrophy or dilation

Auscultation

Finding	Description	Associated Conditions
Regular tachycardia	Rapid, regular rhythm; unable to count individually	Supraventricular tachycardia, sinus tachycardia, ventricular tachycardia
Irregular rhythm	Variable R-R intervals on auscultation	Premature beats, atrial fibrillation (rare in children), sinus arrhythmia
Systolic murmur — ejection	Crescendo-decrescendo, harsh, at upper sternal borders	Aortic stenosis, pulmonary stenosis, hypertrophic cardiomyopathy (increases with Valsalva)
Systolic murmur — regurgitant	Holosystolic, blowing	Mitral regurgitation (apex), tricuspid regurgitation (lower left sternal border), ventricular septal defect (left sternal border)
Diastolic murmur	After S2; always pathological	Aortic regurgitation, mitral stenosis (rare in children unless rheumatic)
Continuous murmur	Throughout systole and diastole	Patent ductus arteriosus, arteriovenous malformation, venous hum (benign)
Systolic click	Mid-systolic click, may have late systolic murmur	Mitral valve prolapse (associated with palpitations and supraventricular tachycardia)
S3 gallop	Low-pitched sound in early diastole	Normal in children; pathological if associated with heart failure or dilated cardiomyopathy
S4 gallop	Late diastolic sound before S1	Always pathological — suggests decreased ventricular compliance (hypertrophy, cardiomyopathy)
Rub	Scratchy, may vary with position and respiration	Pericarditis (may be associated with myocarditis)

Respiratory Examination

Respiratory rate: Tachypnea may indicate heart failure or anxiety
Work of breathing: Intercostal or subcostal retractions suggest cardiac or respiratory compromise
Auscultation: Crackles may indicate pulmonary edema (heart failure); wheezes may be “cardiac asthma”
Percussion: Dullness at bases may indicate pleural effusions (heart failure)

Abdominal Examination

Hepatomegaly: Liver edge greater than 2 cm below costal margin may indicate right heart failure
Splenomegaly: May suggest infective endocarditis or systemic illness
Ascites: Late sign of right heart failure
Hepatojugular reflux: Sustained JVP elevation with abdominal pressure suggests heart failure

Extremities Examination

Peripheral pulses: Compare upper and lower extremity pulses; radiofemoral delay suggests coarctation of aorta
Clubbing: Suggests chronic cyanotic heart disease or infective endocarditis
Cyanosis: Central (lips, tongue) vs peripheral (fingers, toes); indicates right-to-left shunting
Edema: Peripheral edema (less common in children than adults as heart failure sign)
Capillary refill: Prolonged (greater than 2-3 seconds) suggests poor perfusion
Marfanoid habitus: Long limbs, arachnodactyly (thumb sign, wrist sign), joint hypermobility — associated with mitral valve prolapse and arrhythmias
Skin changes: Mottling, cool extremities suggest poor cardiac output

Syndrome-Associated Features to Look For

Syndrome	Physical Features	Associated Cardiac Abnormalities
Marfan syndrome	Tall stature, long limbs, arachnodactyly, pectus deformity, lens dislocation, high arched palate	Mitral valve prolapse, aortic root dilation, arrhythmias
Noonan syndrome	Short stature, webbed neck, low-set ears, hypertelorism, pectus deformity	Pulmonary stenosis, hypertrophic cardiomyopathy, atrial septal defect
Turner syndrome	Short stature, webbed neck, wide-spaced nipples, lymphedema	Bicuspid aortic valve, coarctation, aortic dissection risk
Williams syndrome	Elfin facies, developmental delay, hypercalcemia, friendly personality	Supravalvar aortic stenosis, peripheral pulmonary stenosis
Down syndrome	Characteristic facies, hypotonia, single palmar crease	Atrioventricular septal defect, ventricular septal defect, tetralogy of Fallot

Expected Findings by Etiology

Condition	General/Vital Signs	Cardiovascular	Other Findings
Benign premature beats	Normal vital signs	Irregular rhythm; normal heart sounds; no murmur	Completely normal examination
Supraventricular tachycardia (between episodes)	Normal vital signs	Regular rhythm; normal heart sounds; usually no murmur	Usually completely normal
Supraventricular tachycardia (during episode)	Tachycardia (180-300 bpm); BP may be low if prolonged	Very rapid regular rhythm; S1 variable intensity	Pallor, diaphoresis if hemodynamically affected; infants may have hepatomegaly
Wolff-Parkinson-White syndrome (baseline)	Normal vital signs	Usually normal; may have mild tachycardia at rest	Usually completely normal
Postural orthostatic tachycardia syndrome	Normal supine; HR increase ≥40 bpm on standing	Tachycardia on standing; no murmur	May appear anxious; acrocyanosis of dependent extremities on standing
Anxiety/panic disorder	Mild tachycardia; tachypnea; may hyperventilate	Regular rhythm; no murmur	Anxious appearance; tremor; diaphoresis; normal between episodes
Hyperthyroidism	Tachycardia; widened pulse pressure; tremor	Hyperdynamic precordium; possible flow murmur	Goiter; proptosis; lid lag; weight loss; hyperreflexia
Anemia	Tachycardia; tachypnea	Flow murmur; hyperdynamic precordium	Pallor (conjunctivae, palms); fatigue; possibly splenomegaly
Myocarditis	Tachycardia disproportionate to fever; may have fever	Gallop rhythm (S3); possible murmur of mitral regurgitation	Recent viral illness; hepatomegaly; respiratory distress if heart failure
Hypertrophic cardiomyopathy	Usually normal vital signs	Systolic ejection murmur (increases with Valsalva); S4; double apical impulse	May have syncope history; family history of sudden death

Important Teaching Point

A normal physical examination is very common in pediatric palpitations! The majority of children with palpitations — including those with significant arrhythmias such as supraventricular tachycardia and Wolff-Parkinson-White syndrome — have completely normal examinations between episodes. A normal examination does not exclude serious arrhythmia. The key is capturing the rhythm during symptoms through ECG, Holter monitor, event recorder, or smartwatch.

Clinical Pearl — The Active Stand Test

If postural orthostatic tachycardia syndrome is suspected, perform an active standing test during the office visit. Have the patient lie supine for 5 minutes, measure heart rate and blood pressure, then have them stand still (without walking) and remeasure at 1, 3, 5, and 10 minutes. A heart rate increase of 40 bpm or more (or absolute HR greater than 120 bpm) within 10 minutes of standing, without orthostatic hypotension, combined with symptoms of orthostatic intolerance, supports the diagnosis. This simple test can be done without specialized equipment.

5. Differential Diagnosis

Systematic approach organized by probability and clinical features in pediatric patients

The differential diagnosis of pediatric palpitations spans a wide range from benign to life-threatening conditions. A systematic, probability-based approach helps prioritize evaluation while ensuring serious conditions are not missed. Remember that the vast majority (85-90%) of pediatric palpitations are benign, but identifying the minority with serious pathology is critical.

Overview: Differential Diagnosis by Probability

Probability	Category	Conditions	Approximate Frequency
COMMON	Benign/Physiologic	Sinus tachycardia, sinus arrhythmia, premature atrial contractions, premature ventricular contractions, anxiety	~85%
LESS COMMON	Supraventricular arrhythmias	Supraventricular tachycardia, Wolff-Parkinson-White syndrome, atrioventricular nodal re-entrant tachycardia, atrial flutter	~10%
LESS COMMON	Autonomic dysfunction	Postural orthostatic tachycardia syndrome, inappropriate sinus tachycardia, vasovagal syncope prodrome	~3%
UNCOMMON BUT SERIOUS	Ventricular arrhythmias/Channelopathies	Long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, ventricular tachycardia	~1-2%
UNCOMMON BUT SERIOUS	Structural heart disease	Cardiomyopathy, myocarditis, congenital heart disease, arrhythmogenic right ventricular cardiomyopathy	~1%

Step-by-Step Approach to Pediatric Palpitations

Systematic Evaluation Framework:

Step 1: Identify red flags — Syncope, exertional symptoms, family history of sudden death, structural heart disease
Step 2: Characterize the palpitations — Regular vs irregular, fast vs normal rate, abrupt vs gradual onset
Step 3: Consider age-specific causes — Certain conditions more common at different ages
Step 4: Obtain baseline ECG — Look for pre-excitation, long QT, Brugada pattern, ventricular hypertrophy
Step 5: Rule out secondary causes — Anemia, thyroid disease, medications, substances, anxiety
Step 6: Capture the rhythm during symptoms — Event recorder, Holter monitor, or smartwatch if diagnosis unclear

Differential by Presentation Pattern

Rapid, Regular Palpitations

Probability	Condition	Typical Rate	Key Features	Red Flags
COMMON	Sinus tachycardia	Age-appropriate (rarely exceeds 200 bpm in children)	Gradual onset/offset; secondary cause present (fever, pain, anxiety, dehydration)	Persistent without identifiable cause
LESS COMMON	Supraventricular tachycardia (atrioventricular re-entrant tachycardia)	180-300 bpm (infants often >220)	Abrupt onset/offset; “like a light switch”; may feel neck pounding	Syncope; prolonged episodes; hemodynamic compromise
LESS COMMON	Atrioventricular nodal re-entrant tachycardia	150-250 bpm	Abrupt onset/offset; more common in older children/adolescents; neck pounding (cannon A waves)	Syncope; chest pain
LESS COMMON	Atrial flutter	Atrial rate 250-350; ventricular rate depends on block	May be regular (fixed block) or irregular (variable block); more common post-cardiac surgery	Structural heart disease; heart failure symptoms
UNCOMMON	Ventricular tachycardia	150-250 bpm	May be regular; wide QRS on ECG; hemodynamic compromise more common	Syncope; known cardiomyopathy; structural heart disease
UNCOMMON	Automatic atrial tachycardia	130-250 bpm	Often incessant; gradual onset (warm-up); may cause tachycardia-induced cardiomyopathy	Persistent tachycardia; signs of heart failure

Irregular Palpitations (Skipped or Extra Beats)

Probability	Condition	Key Features	ECG Findings	Red Flags
VERY COMMON	Sinus arrhythmia	Heart rate varies with respiration; completely benign; very common in children	Normal P waves; rate increases with inspiration	None — this is normal
COMMON	Premature atrial contractions	Single skipped beat sensation; often at rest; may increase with caffeine or fatigue	Early P wave with different morphology; usually narrow QRS	Very frequent (>10% burden); associated with structural abnormality
COMMON	Premature ventricular contractions	“Flip-flop” sensation; compensatory pause; more forceful post-ectopic beat	Wide QRS; no preceding P wave; compensatory pause	Frequent (>10-15%); runs of ventricular tachycardia; symptoms with exercise; structural heart disease
UNCOMMON	Atrial fibrillation	Irregularly irregular; rare in children without structural heart disease	No P waves; irregular R-R intervals; fibrillatory baseline	Any atrial fibrillation in a child requires evaluation for underlying cause

Position-Related Palpitations

Probability	Condition	Key Features	Diagnostic Criteria	Associated Symptoms
INCREASINGLY RECOGNIZED	Postural orthostatic tachycardia syndrome	Palpitations and tachycardia with standing; improves lying down; female predominance	HR increase ≥40 bpm within 10 min of standing (or HR >120 bpm) without orthostatic hypotension	Lightheadedness, fatigue, brain fog, exercise intolerance, nausea
COMMON	Orthostatic hypotension with compensatory tachycardia	Palpitations on standing with lightheadedness; dehydration common trigger	BP drop >20/10 mmHg on standing with compensatory HR increase	Lightheadedness, tunnel vision, near-syncope
COMMON	Vasovagal prodrome	Palpitations as part of pre-syncopal symptoms; often with specific triggers	History of vasovagal syncope; prodromal symptoms before fainting	Nausea, warmth, diaphoresis, pallor preceding syncope

Age-Based Differential Considerations

Age Group	Most Common Causes	Important Considerations	Conditions to Rule Out
Infants (0-1 year)	Supraventricular tachycardia (especially atrioventricular re-entrant tachycardia with accessory pathway)	Cannot verbalize; presents with irritability, poor feeding, pallor, lethargy	Wolff-Parkinson-White syndrome, congenital heart disease, myocarditis
Toddlers (1-3 years)	Supraventricular tachycardia, sinus tachycardia (fever, illness)	May be able to tap rhythm; parental observation important	Accessory pathway-mediated tachycardia, automatic atrial tachycardia
School-age (4-11 years)	Premature beats, sinus tachycardia, supraventricular tachycardia, anxiety	Can describe symptoms; often related to exercise or emotions	Atrioventricular nodal re-entrant tachycardia, long QT syndrome, catecholaminergic polymorphic ventricular tachycardia
Adolescents (12-18 years)	Anxiety, postural orthostatic tachycardia syndrome, premature beats, caffeine-related, atrioventricular nodal re-entrant tachycardia	Screen for substances (energy drinks, drugs); anxiety very common; female predominance for postural orthostatic tachycardia syndrome	Long QT syndrome, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy

Anatomical Approach to Arrhythmia Origin

Sinus Node

Sinus tachycardia

Sinus bradycardia

Sinus arrhythmia

Inappropriate sinus tachycardia

Sick sinus syndrome (post-surgical)

Atrial

Premature atrial contractions

Atrial tachycardia (automatic or re-entrant)

Atrial flutter

Atrial fibrillation (rare)

Multifocal atrial tachycardia

Atrioventricular Junction

Atrioventricular nodal re-entrant tachycardia

Atrioventricular re-entrant tachycardia (accessory pathway)

Junctional ectopic tachycardia

Permanent junctional reciprocating tachycardia

Wolff-Parkinson-White syndrome

Ventricular

Premature ventricular contractions

Ventricular tachycardia (monomorphic)

Ventricular tachycardia (polymorphic)

Catecholaminergic polymorphic ventricular tachycardia

Torsades de pointes (long QT syndrome)

Channelopathies and Inherited Arrhythmia Syndromes

Life-Threatening Conditions to Consider

These conditions are uncommon but carry significant risk of sudden cardiac death if undiagnosed:

Condition	Typical Presentation	ECG Clues	Triggers	Inheritance
Long QT syndrome Type 1	Syncope or palpitations with exercise, especially swimming	Prolonged QTc (>470 ms males, >480 ms females); broad-based T waves	Exercise, swimming, diving	Autosomal dominant (KCNQ1)
Long QT syndrome Type 2	Syncope or palpitations with auditory stimuli, emotion, or postpartum	Prolonged QTc; low amplitude, notched T waves	Auditory startle, emotion, rest	Autosomal dominant (KCNH2)
Long QT syndrome Type 3	Events during rest or sleep	Prolonged QTc; late-onset T waves; long ST segment	Rest, sleep, bradycardia	Autosomal dominant (SCN5A)
Catecholaminergic polymorphic ventricular tachycardia	Syncope or palpitations strictly with exercise or emotion	Normal baseline ECG; bidirectional or polymorphic ventricular tachycardia with exercise	Exercise, emotional stress	Autosomal dominant (RYR2) or recessive (CASQ2)
Brugada syndrome	Syncope, nocturnal agonal breathing, sudden death; often during rest/sleep	Coved ST elevation in V1-V3; may be intermittent or unmasked by fever	Rest, sleep, fever	Autosomal dominant (SCN5A and others)
Arrhythmogenic right ventricular cardiomyopathy	Palpitations, syncope, or cardiac arrest with exercise; adolescent onset typical	Epsilon waves; T wave inversions V1-V3; ventricular ectopy of right ventricular origin	Exercise (especially endurance)	Autosomal dominant (desmosomal genes)

Drug and Substance-Induced Palpitations

Substance/Drug Class	Mechanism	Type of Palpitation	Important Considerations
Caffeine (energy drinks, coffee)	Adenosine receptor antagonism; catecholamine release	Sinus tachycardia, premature beats	Very common in adolescents; energy drinks may contain 200-500 mg caffeine
Stimulants (methylphenidate, amphetamines)	Increased catecholamine activity	Sinus tachycardia, premature beats	Commonly prescribed for ADHD; baseline ECG recommended before starting
Beta-agonists (albuterol, salbutamol)	Beta-adrenergic stimulation	Sinus tachycardia, tremor	Common in asthma treatment; dose-related effect
Decongestants (pseudoephedrine)	Sympathomimetic	Sinus tachycardia, hypertension	Over-the-counter availability; often overlooked
QT-prolonging drugs	Block potassium channels; prolong repolarization	Torsades de pointes (ventricular tachycardia)	Azithromycin, ondansetron, antipsychotics, some antihistamines; risk higher with baseline long QT
Cannabis/THC	Autonomic effects; varies by dose	Tachycardia (acute); bradycardia (chronic)	Increasingly common in adolescents; may exacerbate anxiety
Cocaine	Blocks catecholamine reuptake; sodium channel effects	Sinus tachycardia, ventricular arrhythmias	Can cause coronary vasospasm and myocardial ischemia even in young patients
Pre-workout supplements	Various stimulants (caffeine, synephrine, others)	Sinus tachycardia, premature beats	Contents may not be accurately labeled; common in athletic adolescents
Nicotine (vaping, cigarettes)	Catecholamine release	Sinus tachycardia	Vaping increasingly common; may be higher nicotine concentration than cigarettes

Secondary Causes — Non-Cardiac Conditions

Condition	Mechanism	Associated Features	Screening Test
Anxiety/Panic disorder	Sympathetic activation; heightened interoception	Worry, fear, somatic symptoms; may occur at rest or with stress	Clinical assessment; screening questionnaires (GAD-7, PHQ-A)
Hyperthyroidism	Increased beta-adrenergic sensitivity; direct cardiac effects	Weight loss, heat intolerance, tremor, goiter, exophthalmos	TSH, free T4
Anemia	Compensatory increased cardiac output	Pallor, fatigue, exercise intolerance; heavy menses in adolescent females	Complete blood count
Fever/Infection	Increased metabolic demand; inflammatory mediators	Temperature elevation; infectious symptoms	Temperature; infection workup as indicated
Pheochromocytoma	Catecholamine excess	Paroxysmal hypertension, headache, diaphoresis, pallor	24-hour urine catecholamines/metanephrines; plasma metanephrines
Hypoglycemia	Counter-regulatory catecholamine surge	Tremor, diaphoresis, confusion, hunger; diabetic patients on insulin	Blood glucose during symptoms

Quick Reference: “If You See This, Think This First”

Clinical Clue	Think This First	Next Step
Abrupt onset/offset, very rapid, regular	Supraventricular tachycardia (re-entrant mechanism)	ECG during episode; event monitor; pediatric cardiology referral
Skipped beats at rest, otherwise well	Benign premature beats	ECG; reassurance if normal; Holter if frequent
Syncope with exercise	Channelopathy or cardiomyopathy	Urgent ECG; restrict activity; pediatric cardiology urgent referral
Palpitations during swimming	Long QT syndrome type 1	ECG with QTc measurement; restrict swimming; genetics referral
Palpitations with auditory startle	Long QT syndrome type 2	ECG with QTc measurement; cardiology evaluation
Symptoms only with standing	Postural orthostatic tachycardia syndrome	Orthostatic vital signs; tilt table test if needed
Family history of sudden death under age 40	Inherited arrhythmia syndrome	ECG; consider genetic testing; family screening
Adolescent with energy drink use	Caffeine-induced sinus tachycardia/ectopy	Trial of caffeine elimination; ECG
Delta wave on ECG	Wolff-Parkinson-White syndrome	Pediatric cardiology referral; risk stratification; consider ablation
Associated anxiety symptoms	Anxiety/panic disorder (but still evaluate cardiac causes)	ECG to rule out cardiac cause; mental health referral if appropriate
Infant with irritability and poor feeding during episodes	Supraventricular tachycardia	ECG; urgent pediatric cardiology evaluation
Post-cardiac surgery patient	Incisional re-entrant tachycardia or atrial flutter	ECG; cardiology follow-up; may need electrophysiology study

6. Diagnostic Investigations

A stepwise, evidence-based approach guided by clinical suspicion in pediatric patients

The diagnostic workup for pediatric palpitations should be guided by the clinical presentation, presence of red flags, and pre-test probability of significant arrhythmia. The primary goal is to capture a rhythm strip during symptoms. A normal ECG between episodes does not exclude serious arrhythmia.

Baseline Investigations for All Patients

Investigation	Purpose	What to Look For	Practical Points
12-lead ECG	Screen for pre-excitation, long QT, Brugada pattern, ventricular hypertrophy, arrhythmia	Delta wave (Wolff-Parkinson-White), prolonged QTc, ST-T abnormalities, ectopy, chamber enlargement	Essential first test; use age-appropriate normal values; measure QTc in lead II or V5
Blood pressure	Screen for hypertension; assess hemodynamics	Elevated BP (use age/height percentiles); orthostatic changes	Use appropriate cuff size; consider 4-limb BP if coarctation suspected
Orthostatic vital signs	Evaluate for postural orthostatic tachycardia syndrome or orthostatic hypotension	HR increase ≥40 bpm on standing (ages 12-19); BP drop >20/10 mmHg	Measure supine (after 5 min rest) then standing at 0, 3, 5, 10 minutes

Key ECG Measurements and Age-Appropriate Values

QTc (corrected QT interval):

Normal: ≤440 ms (males), ≤450 ms (females)
Borderline: 441-469 ms (males), 451-479 ms (females)
Prolonged: ≥470 ms (males), ≥480 ms (females)

PR Interval (age-dependent):

Infants: 80-120 ms
Children: 100-160 ms
Adolescents: 120-200 ms
Short PR (<120 ms) with delta wave = Wolff-Parkinson-White

Second-Tier Investigations (Based on Initial Evaluation)

Investigation	Indication	What It Detects	Pediatric Considerations
Complete blood count	Fatigue, pallor, heavy menses, tachycardia without clear cause	Anemia (low hemoglobin)	Iron deficiency common in adolescent females; hemoglobin normal range varies with age
Thyroid function tests (TSH, free T4)	Weight changes, heat/cold intolerance, tremor, goiter	Hyperthyroidism or hypothyroidism	Graves disease is most common cause of hyperthyroidism in children
Basic metabolic panel	Concurrent illness, medications, suspected electrolyte abnormality	Hypokalemia, hypomagnesemia, hypocalcemia (can cause arrhythmias)	Electrolyte abnormalities can trigger arrhythmias in predisposed patients
Urine drug screen	Adolescents with concerning history; unexplained tachyarrhythmias	Cocaine, amphetamines, cannabis	Consider with appropriate counseling and consent; may not detect all synthetic drugs

Rhythm Monitoring — Capturing the Arrhythmia

Key Principle: The goal of rhythm monitoring is to capture a recording during symptoms. A captured rhythm during symptoms is worth more than any number of normal ECGs or negative monitors. Match the monitoring duration to symptom frequency.

Monitor Type	Duration	Best For	Pediatric Considerations
24-48 hour Holter monitor	24-48 hours continuous recording	Daily or near-daily symptoms; quantifying ectopy burden	Well-tolerated in children; patient/parent diary essential; calculate premature beat burden
Extended Holter (7-14 day patch monitor)	1-2 weeks continuous recording	Symptoms several times per week	Adhesive patches (e.g., Zio patch) comfortable; waterproof options available
Event recorder (patient-activated)	2-4 weeks	Symptoms weekly to monthly; patient can activate during symptoms	Requires patient cooperation; may miss very brief episodes; good for older children/adolescents
Mobile cardiac telemetry	Up to 30 days continuous with real-time transmission	Suspected serious arrhythmia; high-risk patients	Auto-detection of arrhythmias; useful when immediate notification needed
Implantable loop recorder	Up to 3 years	Rare but significant symptoms; syncope of unclear etiology	Small device implanted subcutaneously; requires minor procedure; reserved for difficult cases
Smartwatch/Consumer wearable	Continuous (when worn)	Capturing heart rate during symptoms; single-lead ECG capability	Increasingly used; not validated for all arrhythmias; useful adjunct; may capture what monitors miss

Clinical Pearl — Smartwatch Data

Many adolescents and families now have smartwatches capable of recording heart rate trends and single-lead ECGs. Ask about this at every visit! A single-lead ECG captured during symptoms on an Apple Watch or similar device can provide diagnostic information. The heart rate graph during an episode can help differentiate abrupt-onset supraventricular tachycardia from gradual-onset sinus tachycardia. Always review any available wearable data.

Echocardiography

Indication	What to Assess	Findings That Change Management
Murmur on examination	Structural abnormality, valve function	Any structural lesion; mitral valve prolapse (associated with arrhythmias)
Abnormal ECG (other than isolated ectopy)	Ventricular hypertrophy, chamber dilation	Hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy features
Syncope with palpitations	Structural heart disease, cardiomyopathy	Any structural abnormality; reduced ventricular function
Family history of cardiomyopathy or sudden death	Occult cardiomyopathy	Asymmetric septal hypertrophy; right ventricular abnormalities
Frequent premature ventricular contractions (>10% burden)	Left ventricular function; right ventricular assessment	Reduced ejection fraction (tachycardia-induced cardiomyopathy); structural substrate
Suspected myocarditis	Ventricular function, pericardial effusion	Reduced function; wall motion abnormalities; effusion
Documented ventricular tachycardia	Structural substrate for ventricular arrhythmias	Right ventricular dilation/dysfunction (arrhythmogenic right ventricular cardiomyopathy); left ventricular noncompaction

Exercise Stress Testing

Indication	What It Assesses	Key Findings	Pediatric Considerations
Exercise-induced symptoms	Arrhythmia induction with exertion	Supraventricular tachycardia, ventricular tachycardia, catecholaminergic polymorphic ventricular tachycardia pattern	Protocol adjusted for age/size; supervised by personnel trained in pediatric resuscitation
Suspected catecholaminergic polymorphic ventricular tachycardia	Catecholamine-induced ventricular arrhythmias	Bidirectional ventricular tachycardia; polymorphic premature ventricular contractions increasing with exercise	Stop test if bidirectional ventricular tachycardia or polymorphic ventricular tachycardia develops
Long QT syndrome evaluation	QT behavior with exercise; T-wave morphology	Failure of QT to shorten appropriately; T-wave alternans	QTc should shorten with exercise; paradoxical prolongation concerning
Wolff-Parkinson-White risk stratification	Accessory pathway behavior during exercise	Abrupt loss of pre-excitation suggests lower-risk pathway	Does not replace electrophysiology study for risk stratification
Premature ventricular contraction suppression assessment	Ectopy behavior with exertion	Benign premature ventricular contractions often suppress with exercise	Increasing ectopy or ventricular tachycardia with exercise is concerning

Advanced Investigations

Electrophysiology Study

Indications in Pediatrics

Documented supraventricular tachycardia — for diagnosis and ablation
Wolff-Parkinson-White syndrome — risk stratification and ablation
Suspected accessory pathway despite normal ECG
Recurrent arrhythmias requiring intervention
Syncope with non-diagnostic non-invasive workup
Risk stratification in inherited arrhythmia syndromes

Pediatric Considerations

Usually performed under general anesthesia in younger children
Vascular access considerations in small children
Ablation success rates similar to adults for most arrhythmias
Radiation exposure minimized with 3D mapping systems
Risk of heart block in septal accessory pathways
Some centers recommend deferring ablation until older if arrhythmia well-controlled

Cardiac MRI

Indication	What It Assesses	Pediatric Considerations
Suspected arrhythmogenic right ventricular cardiomyopathy	Right ventricular size, function, wall motion; fatty/fibrous infiltration	Gold standard for arrhythmogenic right ventricular cardiomyopathy diagnosis; may need sedation in young children
Myocarditis evaluation	Edema, inflammation, fibrosis (late gadolinium enhancement)	Helps confirm diagnosis and assess extent; gadolinium used in children
Cardiomyopathy evaluation	Detailed anatomy, function, tissue characterization	Better tissue characterization than echocardiography; longer study duration
Complex congenital heart disease	Anatomy, function, flow quantification	Essential for complex anatomy; no radiation

Genetic Testing

Condition	When to Consider	Clinical Utility	Important Notes
Long QT syndrome	Prolonged QTc; family history; unexplained syncope	Confirms diagnosis; identifies type (guides management); enables family screening	Positive in ~75% of clinically diagnosed cases; negative result does not exclude diagnosis
Catecholaminergic polymorphic ventricular tachycardia	Bidirectional ventricular tachycardia; exercise-induced syncope with normal ECG	Confirms diagnosis; family screening	RYR2 (dominant) or CASQ2 (recessive); yield ~60%
Hypertrophic cardiomyopathy	Clinical diagnosis of hypertrophic cardiomyopathy; family history	Family screening; prognostic information in some cases	Sarcomeric gene mutations; positive in ~30-60%
Arrhythmogenic right ventricular cardiomyopathy	Clinical suspicion; family history	Confirms diagnosis; family screening	Desmosomal gene mutations; penetrance variable
Brugada syndrome	Type 1 Brugada pattern; family history	Family screening; research	SCN5A positive in only ~20-25%; genetic testing less useful for prognosis

Genetic Testing Considerations

Genetic testing for arrhythmia syndromes should be performed with appropriate genetic counseling and ideally coordinated through a specialized cardiac genetics program. Consider:

Implications for the patient and family members
Variants of uncertain significance (common and can cause anxiety)
Insurance implications (genetic non-discrimination laws vary)
Negative results do not exclude clinical diagnosis
Cascade testing of family members if positive

Targeted Investigation Approach by Suspected Etiology

If Suspecting Supraventricular Tachycardia

First-Line Tests

12-lead ECG: Look for delta wave (Wolff-Parkinson-White), short PR interval, atrial abnormalities
Event monitor: Match duration to symptom frequency; capture rhythm during episode
Echocardiography: If abnormal ECG or murmur; assess for structural heart disease or Ebstein anomaly

Second-Line Tests

Electrophysiology study: For diagnosis and ablation; risk stratification in Wolff-Parkinson-White
Exercise stress test: Assess for pathway behavior with exercise

If Suspecting Long QT Syndrome

First-Line Tests

12-lead ECG with QTc measurement: Use Bazett formula; measure in lead II or V5; average multiple beats
Family ECG screening: Screen first-degree relatives
Medication review: Identify QT-prolonging drugs

Second-Line Tests

Exercise stress test: QT behavior during exercise and recovery
Genetic testing: Confirms diagnosis and type; guides therapy and family screening
Holter monitor: Assess for bradycardia, pauses, T-wave alternans

If Suspecting Catecholaminergic Polymorphic Ventricular Tachycardia

First-Line Tests

12-lead ECG: Usually normal at rest (key feature)
Exercise stress test: Essential; reproduces arrhythmia; look for bidirectional or polymorphic ventricular tachycardia

Second-Line Tests

Holter monitor: May capture exercise-related ectopy
Genetic testing: RYR2 or CASQ2 mutations; family screening
Epinephrine provocation: Rarely needed; may unmask arrhythmia

If Suspecting Postural Orthostatic Tachycardia Syndrome

First-Line Tests

Active stand test: Orthostatic vital signs at 0, 3, 5, 10 minutes of standing
12-lead ECG: Rule out underlying cardiac cause
Basic labs: Complete blood count (anemia), TSH (thyroid), basic metabolic panel

Second-Line Tests

Tilt table test: Formal autonomic testing; not always required if active stand test positive
24-hour urine sodium: Assess sodium intake
Consider screening for associated conditions: Ehlers-Danlos syndrome, mast cell activation, autoimmune markers

Investigation Algorithm Summary

Stepwise Diagnostic Approach:

All patients: 12-lead ECG + orthostatic vital signs
If red flags present: Urgent cardiology referral; echocardiography; consider activity restriction
If ECG abnormal: Echocardiography; cardiology referral; further testing based on abnormality
If ECG normal but ongoing symptoms: Rhythm monitoring matched to symptom frequency; consider basic labs
If rhythm captured: Diagnosis guides management; cardiology referral for arrhythmias
If rhythm not captured after appropriate monitoring: Consider longer-term monitoring; smartwatch; event recorder; or implantable loop recorder in select cases

Important Pediatric Investigation Considerations

Radiation exposure: Minimize CT use; prefer echocardiography and MRI when imaging needed
Sedation: Young children may require sedation for MRI; coordinate with anesthesia
Age-appropriate normal values: Use pediatric reference ranges for ECG intervals, heart rate, and lab values
Patient cooperation: Event monitors require child understanding; patch monitors may be better for younger children
Family involvement: Parents essential for diary keeping and symptom documentation

7. Clinical Decision-Making

Practical algorithms and decision pathways for pediatric palpitations

Clinical decision-making in pediatric palpitations requires balancing thoroughness with practicality. Most children will have benign causes, but missing a serious arrhythmia can have devastating consequences. This section provides frameworks for triage, evaluation pathways, and management decisions.

Step 1: Is This Urgent? — Triage Assessment

Clinical Scenario	Urgency Level	Immediate Action	Disposition
Active arrhythmia with hemodynamic instability (hypotension, altered consciousness, poor perfusion)	EMERGENT	ABC assessment; IV access; 12-lead ECG; prepare for cardioversion; call pediatric cardiology	Emergency department; PICU if unstable
Syncope with palpitations (especially exertional)	EMERGENT	ECG immediately; activity restriction; do not discharge until cardiology evaluation	Emergency department; urgent cardiology consult
Palpitations during active episode (hemodynamically stable)	URGENT	12-lead ECG during symptoms (critical); vital signs; IV access if tachyarrhythmia	Emergency department or urgent care with ECG capability
Known Wolff-Parkinson-White with new symptoms	URGENT	ECG; assess for pre-excited atrial fibrillation; contact cardiology	Emergency department; cardiology follow-up within 24-48 hours
Family history of sudden cardiac death with new palpitations	URGENT	ECG with QTc measurement; activity restriction until evaluated	Urgent cardiology referral (within 1-2 weeks); activity restriction
Recurrent palpitations without red flags	SEMI-URGENT	ECG; basic labs if indicated; reassurance; arrange monitoring	Outpatient cardiology referral (within 2-4 weeks)
Isolated episode, no red flags, normal ECG	ROUTINE	ECG; reassurance; education about symptom diary	Primary care follow-up; cardiology if recurrent

Step 2: Classify by Presentation Pattern

Regular, Rapid Palpitations

Key question: Abrupt or gradual onset?

Abrupt: Likely re-entrant SVT → Event monitor, cardiology referral

Gradual: Likely sinus tachycardia → Identify underlying cause

Irregular/Skipped Beats

Key question: How frequent?

Occasional: Likely benign ectopy → Reassurance, Holter if frequent

Frequent/Runs: Need evaluation → Holter, echo if high burden

Position-Related

Key question: Worse standing?

Yes: Likely POTS → Orthostatic vitals, hydration trial

No: Other causes → Standard workup

Step 3: Follow the Appropriate Algorithm

Algorithm A: Palpitations with Syncope

High-Risk Pathway — Do Not Miss

Syncope with palpitations suggests hemodynamically significant arrhythmia until proven otherwise.

Clinical Scenario	Most Likely Diagnosis	Immediate Action	Next Steps
Syncope during exercise	Long QT syndrome, CPVT, hypertrophic cardiomyopathy, ARVC	Activity restriction; ECG with QTc; urgent cardiology	Echo, exercise stress test, genetic testing, possible ICD evaluation
Syncope during swimming	Long QT syndrome type 1 (high suspicion)	No swimming until cleared; ECG; urgent cardiology	Genetic testing; beta-blocker therapy; family screening
Syncope with auditory startle	Long QT syndrome type 2	ECG; avoid alarm clocks/loud sounds; cardiology referral	Genetic testing; beta-blocker therapy; environment modification
Syncope with exertion + family history of sudden death	Inherited channelopathy or cardiomyopathy	Complete activity restriction; urgent cardiology	Full channelopathy/cardiomyopathy workup; family screening
Syncope with rapid regular palpitations preceding	SVT with hemodynamic compromise	ECG; cardiology referral	Event monitor; consider electrophysiology study and ablation

Algorithm B: Recurrent Palpitations Without Syncope

Clinical Scenario	Most Likely Diagnosis	Initial Workup	Management
Abrupt onset/offset, rapid, regular; terminates with vagal maneuvers	Supraventricular tachycardia (re-entrant)	ECG (look for delta wave); event monitor	Teach vagal maneuvers; cardiology referral; consider ablation
Gradual onset, associated with anxiety/stress	Sinus tachycardia (anxiety-related)	ECG; consider anxiety screening	Address anxiety; cognitive behavioral therapy; reassurance
Worse with standing, fatigue, lightheadedness	Postural orthostatic tachycardia syndrome	Orthostatic vitals; ECG; basic labs	Fluids, salt, compression; exercise reconditioning; consider medication
Skipped beats at rest, otherwise well	Benign premature beats (PACs/PVCs)	ECG; Holter if frequent	Reassurance; avoid caffeine; echo if PVC burden >10%
Associated with energy drink or caffeine use	Caffeine-induced ectopy/tachycardia	ECG; detailed substance history	Caffeine elimination trial; follow-up in 2-4 weeks
Delta wave on baseline ECG	Wolff-Parkinson-White syndrome	ECG; echo; cardiology referral	Risk stratification; consider electrophysiology study and ablation

Algorithm C: Infant with Suspected Arrhythmia

Presentation	Most Likely Diagnosis	Immediate Action	Management
Irritability, poor feeding, pallor, tachycardia >220 bpm	Supraventricular tachycardia	12-lead ECG; ice to face (vagal); IV access	Adenosine if stable; cardioversion if unstable; cardiology consult
Intermittent episodes of pallor and fussiness	Paroxysmal SVT	ECG during episode if possible; Holter monitor	Cardiology referral; may need prophylactic medication
Irregular pulse noted on examination	Premature beats (usually benign) vs other	ECG; Holter if frequent	Usually benign; reassurance; follow-up
Fetal SVT history, now symptomatic	Recurrent SVT	ECG; monitor; cardiology	May need prophylaxis; many outgrow by age 1 year

“What Do I Do If…” Decision Reference

Clinical Situation	Immediate Action	Next Step
ECG shows prolonged QTc (>470 ms male, >480 ms female)	Review medications; stop QT-prolonging drugs; activity restriction	Urgent cardiology referral; family ECG screening; genetic testing
ECG shows delta wave (Wolff-Parkinson-White pattern)	Inform family of diagnosis; avoid AV nodal blocking drugs if atrial fibrillation develops	Cardiology referral for risk stratification; consider electrophysiology study
Holter shows >10% PVC burden	Obtain echocardiogram to assess ventricular function	Cardiology referral; may need treatment to prevent cardiomyopathy
Child has SVT and parents want to know about sports	Depends on SVT type and control; generally can participate if well-controlled	Cardiology guidance; consider ablation for definitive cure before competitive sports
Adolescent wants to start ADHD medication	Baseline ECG; assess for family history of sudden death or arrhythmia	If ECG normal and no concerning history, can proceed; monitor for palpitations
Family history of long QT syndrome, child asymptomatic	ECG with QTc measurement	Genetic testing if family mutation known; cardiology referral; family screening
Palpitations with normal ECG and normal Holter	Reassurance if no red flags; consider longer monitoring if symptoms persist	Extended monitoring (2-4 week event recorder); address anxiety if present
Suspected POTS with positive orthostatic test	Begin conservative management: fluids (2-3 L/day), salt (3-5 g/day), compression	Exercise reconditioning program; cardiology or autonomic specialist if refractory
Anxiety appears to be driving symptoms	Complete cardiac workup to reassure; validate symptoms	Mental health referral; cognitive behavioral therapy; avoid repeated cardiac testing
Parent asking about catheter ablation for child’s SVT	Discuss success rates (>95%), risks (1-2% complication rate), alternatives	Consider age, frequency of episodes, medication tolerance; shared decision-making

When to Refer to Pediatric Cardiology

Urgent Referral (Within 1-2 Weeks)

Syncope with palpitations
Exertional symptoms
Family history of sudden cardiac death <40 years
Abnormal ECG (prolonged QT, delta wave, Brugada pattern)
Documented arrhythmia on monitoring
Structural heart disease
Palpitations in patient with known congenital heart disease

Routine Referral (Within 4-6 Weeks)

Recurrent palpitations without red flags
Frequent premature beats on Holter (>1% burden)
Suspected SVT not yet documented
POTS not responding to conservative management
Murmur associated with palpitations
Parental anxiety requiring specialist reassurance

Troubleshooting: Refractory Palpitations

When Symptoms Persist Despite Negative Workup

Ask these questions before concluding the evaluation is complete:

Was rhythm captured during symptoms? A normal ECG or Holter between episodes does not exclude arrhythmia
Was monitoring duration adequate? Match monitor duration to symptom frequency
Were all secondary causes evaluated? Thyroid, anemia, medications, substances
Was orthostatic testing performed? POTS is commonly missed
Was exercise testing done if exertional symptoms? CPVT has normal resting ECG
Is anxiety contributing? Can coexist with or mimic cardiac causes
Would longer-term monitoring help? Consider implantable loop recorder for rare but significant symptoms
Is the family satisfied with the explanation? Address concerns to prevent “doctor shopping”

Activity and Sports Participation Guidance

Condition	Restriction Level	Guidance
Benign premature beats, normal heart	No restriction	Full participation in all activities
SVT, well-controlled or post-ablation	Usually no restriction	Full participation if asymptomatic on/off medication; cardiology clearance
Wolff-Parkinson-White, asymptomatic	Individualized	Risk stratification needed; many can participate; consider ablation before competitive sports
Long QT syndrome	Restricted	No competitive sports; no swimming alone; avoid QT-prolonging drugs; cardiology guidance
CPVT	Significantly restricted	No competitive sports; limit exercise intensity; beta-blocker therapy essential
Hypertrophic cardiomyopathy	Restricted	No competitive sports in most cases; individualized risk assessment
POTS	Encourage exercise	Exercise is therapeutic; may need modified approach initially; gradual reconditioning
Pending evaluation with red flags	Temporarily restricted	No strenuous activity until cleared by cardiology

8. Clinical Pearls and Pitfalls

Practical wisdom — learn from experience and avoid common mistakes

Must-Know Clinical Pearls

Capture the rhythm during symptoms: A single ECG or rhythm strip during symptoms is more valuable than multiple normal ECGs or negative Holter monitors obtained between episodes. Encourage families to use smartwatches, go to the ED during symptoms, or have the child tap out the rhythm.

Abrupt onset/offset = re-entry: The hallmark of re-entrant supraventricular tachycardia (and Wolff-Parkinson-White syndrome) is the “light switch” pattern — sudden start and sudden stop. This distinguishes it from sinus tachycardia, which ramps up and down gradually.

Syncope + palpitations + exercise = high risk: This triad suggests a potentially life-threatening channelopathy (long QT syndrome, CPVT) or cardiomyopathy until proven otherwise. Restrict activity and pursue urgent evaluation.

Family history matters enormously: Sudden death under age 40, drowning, single-car accidents, “seizures,” pacemakers/ICDs in family members — all are red flags for inherited arrhythmia syndromes. A thorough three-generation family history is essential.

CPVT has a normal resting ECG: Catecholaminergic polymorphic ventricular tachycardia is characterized by a completely normal baseline ECG. The arrhythmia only appears with exercise or emotion. If you suspect CPVT, an exercise stress test is essential — a normal ECG does not exclude it.

Swimming-related symptoms = long QT type 1: Palpitations, near-drowning, or syncope during swimming should raise immediate suspicion for long QT syndrome type 1. Restrict swimming until evaluated.

Infants can’t tell you their heart is racing: SVT in infants presents with nonspecific symptoms: irritability, poor feeding, pallor, lethargy. By the time symptoms are obvious, the infant may have been in SVT for hours and be developing heart failure. Maintain a high index of suspicion.

POTS is common and commonly missed: Postural orthostatic tachycardia syndrome is increasingly recognized in adolescents, especially females. A simple standing test in the office can make the diagnosis. Symptoms improve lying down.

Ask about energy drinks: Adolescents may consume massive amounts of caffeine through energy drinks (200-500 mg per can). This is a common and easily reversible cause of palpitations that is often not volunteered unless specifically asked.

Anxiety and arrhythmia can coexist: Don’t assume palpitations are “just anxiety” without proper evaluation. Conversely, after ruling out cardiac causes, address anxiety appropriately — it’s a real condition that causes real symptoms and deserves treatment.

Critical Pitfalls to Avoid

Assuming a normal ECG excludes serious arrhythmia: Many dangerous conditions (CPVT, intermittent SVT, paroxysmal arrhythmias) have completely normal ECGs between episodes. A normal ECG provides reassurance only if the diagnosis is not a paroxysmal arrhythmia.

Dismissing exertional symptoms as “being out of shape”: Syncope, presyncope, or palpitations with exercise in a child should never be attributed to deconditioning without proper cardiac evaluation. This is how channelopathies and cardiomyopathies are missed.

Using adult QTc cutoffs in children: While QTc >500 ms is clearly prolonged at any age, borderline values require age and sex-specific interpretation. A QTc of 460 ms in a prepubertal male is more concerning than in an adolescent female.

Giving adenosine for wide-complex tachycardia without expert guidance: In Wolff-Parkinson-White syndrome with pre-excited atrial fibrillation, AV nodal blocking agents can be dangerous. Wide-complex tachycardia in a child should prompt cardiology consultation before treatment.

Not asking about family history of “seizures”: Arrhythmic syncope can cause hypoxic convulsions that are misdiagnosed as epilepsy. A family history of “seizures” may actually represent inherited arrhythmia syndrome. Ask specifically about circumstances of seizures.

Labeling palpitations as “anxiety” without cardiac workup: While anxiety is common and can cause palpitations, this should be a diagnosis of exclusion. At minimum, obtain an ECG before attributing symptoms to anxiety. Anxiety and arrhythmia can coexist.

Forgetting to review the medication list for QT-prolonging drugs: Many common medications prolong the QT interval (azithromycin, ondansetron, certain antihistamines, antipsychotics). In a patient with borderline long QT or known long QT syndrome, these can be dangerous.

Assuming Wolff-Parkinson-White is always benign: While most patients with Wolff-Parkinson-White do well, there is a small risk of sudden death if atrial fibrillation develops and conducts rapidly over the accessory pathway. Risk stratification by a pediatric electrophysiologist is important.

Not following up on frequent PVCs: While isolated PVCs are often benign, a high burden (>10-15%) can cause tachycardia-induced cardiomyopathy over time. These patients need echocardiographic monitoring and may need treatment.

Inadequate monitoring duration: If symptoms occur weekly, a 24-hour Holter is unlikely to capture them. Match monitoring duration to symptom frequency — this seems obvious but is commonly overlooked.

Key Takeaways

Most pediatric palpitations are benign — approximately 85-90% have no serious underlying cause, but thorough evaluation is needed to identify the minority with dangerous conditions.
The ECG is the essential first test — look for pre-excitation (delta wave), prolonged QTc, and signs of structural heart disease. Use age-appropriate normal values.
Capture the rhythm during symptoms — this is the single most valuable diagnostic information. Encourage use of smartwatches, ED visits during episodes, and appropriate monitoring.
Red flags require urgent evaluation — syncope with palpitations, exertional symptoms, and family history of sudden death under age 40 should prompt immediate activity restriction and urgent cardiology referral.
Family history is critical — many life-threatening arrhythmias are inherited. A three-generation pedigree focusing on sudden death, drowning, seizures, and pacemakers/ICDs is essential.
Abrupt onset/offset suggests re-entrant SVT — this clinical feature reliably distinguishes re-entrant tachycardia from sinus tachycardia and helps guide evaluation.
Don’t forget secondary causes — caffeine (especially energy drinks), medications (stimulants, QT-prolonging drugs), anemia, and thyroid disease are treatable causes of palpitations.
POTS is common in adolescents — a simple standing test can make the diagnosis. Treatment is primarily non-pharmacologic: fluids, salt, compression, and exercise reconditioning.
Normal exam and normal ECG between episodes doesn’t exclude arrhythmia — many serious arrhythmias (SVT, CPVT, long QT syndrome) can have completely normal findings between episodes.
Address anxiety appropriately — after ruling out cardiac causes, anxiety deserves proper treatment. Repeated cardiac testing in anxious patients without new symptoms is counterproductive.

Quick Reference Algorithm

Systematic Approach to Pediatric Palpitations:

Assess for red flags: Syncope, exertional symptoms, family history of sudden death, known heart disease
Obtain 12-lead ECG: Look for pre-excitation, prolonged QTc, Brugada pattern, ectopy, hypertrophy
Perform orthostatic vital signs: Screen for POTS (especially in adolescents with positional symptoms)
Take detailed history: Use “HEARTS” mnemonic; characterize onset/offset pattern; ask about substances
If red flags present: Activity restriction + urgent cardiology referral + echocardiography
If ECG abnormal: Cardiology referral; further testing based on specific abnormality
If history suggests arrhythmia but ECG normal: Rhythm monitoring matched to symptom frequency
Consider secondary causes: Check CBC, TSH if indicated; review medications and substances
If rhythm captured and diagnosis confirmed: Condition-specific management; cardiology follow-up
If workup negative and no red flags: Reassurance; address anxiety if present; follow-up if recurrent

Quick Reference: When to Worry

Feature	Low Concern	High Concern
Associated symptoms	None, or mild anxiety	Syncope, presyncope, chest pain, dyspnea
Timing	At rest, with stress/anxiety	During exercise, swimming, with startle
Pattern	Gradual onset/offset; skipped beats	Abrupt onset/offset; sustained rapid rate
Family history	No cardiac disease	Sudden death <40, arrhythmias, cardiomyopathy, pacemaker/ICD
ECG	Normal; isolated premature beats	Delta wave, prolonged QTc, Brugada pattern, VT
Known conditions	None	Congenital heart disease, cardiomyopathy, prior cardiac surgery