Overview/Definition
Definition:
• Pediatric ECG interpretation requires understanding of age-specific normal variations and developmental changes in cardiac electrophysiology from birth through adolescence
Critical diagnostic tool for detecting congenital heart disease, arrhythmias, and acquired cardiac conditions with interpretation significantly different from adult ECGs.
Epidemiology:
• ECG abnormalities found in approximately 0.5-2% of healthy children during routine screening, with higher prevalence in children with congenital heart disease (>90%), cardiomyopathy, or channelopathies
False positive rates for pathological findings decrease with age-appropriate interpretation using pediatric-specific criteria and normal value ranges.
Age Distribution:
• Neonatal ECGs show dominant right ventricular forces, high heart rates (110-150 bpm), and incomplete RBBB patterns
Infant ECGs (1 month-2 years) demonstrate gradual transition to left ventricular dominance
Child ECGs (2-12 years) approach adult patterns but retain age-specific variations
Adolescent ECGs similar to adults but maintain some pediatric characteristics.
Clinical Significance:
• Essential high-yield topic for DNB Pediatrics and NEET SS examinations focusing on age-specific normal values, pathological rhythm recognition, and congenital heart disease ECG patterns
Critical for sports participation clearance, syncope evaluation, and family history screening for sudden cardiac death
Foundation for pediatric cardiology subspecialty training.
Age-Specific Considerations
Newborn:
• Neonatal ECGs (0-28 days) show physiological right heart dominance with tall R waves in V1-V3, deep S waves in V5-V6
Normal heart rate 110-150 bpm, PR interval 0.08-0.12 seconds, QRS duration <0.08 seconds
T wave inversion in V1-V4 normal (juvenile T wave pattern)
QTC typically 0.38-0.44 seconds.
Infant:
• Infant ECGs (1 month-2 years) demonstrate gradual transition from right to left ventricular dominance
Heart rate 100-150 bpm, PR interval gradually lengthens to 0.10-0.14 seconds
R wave progression in precordial leads shows decreasing R/S ratio in V1 and increasing R waves in V5-V6
T wave inversion persists in V1-V3 throughout infancy.
Child:
• Child ECGs (2-12 years) show continued evolution toward adult patterns with heart rate 60-120 bpm, PR interval 0.10-0.16 seconds, QRS duration 0.06-0.10 seconds
Left ventricular forces become dominant with tall R waves in V5-V6, deep S waves in V1-V2
T wave inversion may persist in V1-V2 until age 8-16 years
QTC remains 0.35-0.44 seconds.
Adolescent:
• Adolescent ECGs (12-18 years) closely resemble adult patterns but may retain some pediatric features like persistent juvenile T wave pattern in V1-V3
Heart rate 50-100 bpm, adult PR and QRS intervals
Early repolarization patterns common and benign
Athletic heart changes may be seen in competitive athletes requiring differentiation from pathology.
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Clinical Presentation
Symptoms:
• Most children with ECG abnormalities are asymptomatic, discovered during routine screening or evaluation for other conditions
Symptomatic presentations may include chest pain, palpitations, syncope, exercise intolerance, or family history screening for sudden cardiac death
Infants may present with poor feeding, irritability, or failure to thrive.
Physical Signs:
• Physical examination may reveal murmurs suggesting structural heart disease, irregular heart rhythms, signs of heart failure (tachypnea, hepatomegaly, poor growth), or signs of genetic syndromes associated with cardiac abnormalities
Blood pressure measurement important for hypertension screening
Growth parameters assessment for failure to thrive.
Severity Assessment:
• Normal ECG variants require no intervention but documentation of normal status
Minor abnormalities may require monitoring or cardiology consultation
Significant abnormalities (pathological arrhythmias, ischemic changes, severe conduction blocks) require immediate cardiology referral and treatment
Life-threatening rhythms require emergency intervention.
Differential Diagnosis:
• ECG abnormalities may represent normal age-related variants, benign findings, or pathological conditions including congenital heart disease, cardiomyopathy, channelopathies (long QT, Brugada, CPVT), myocarditis, electrolyte abnormalities, or medication effects
Clinical correlation essential for accurate interpretation.
Diagnostic Approach
History Taking:
• Detailed cardiac history including chest pain, palpitations, syncope, exercise intolerance, family history of sudden cardiac death, cardiomyopathy, or congenital heart disease
Medication history including QT-prolonging drugs
Birth history for congenital abnormalities
Social history including substance use in adolescents.
Investigations:
• Standard 12-lead ECG with appropriate paper speed (25 mm/sec) and gain (10 mm/mV)
Additional leads (V3R, V4R, V7-V9) if indicated for specific conditions
24-48 hour Holter monitoring for intermittent arrhythmias
Exercise stress testing for exercise-induced arrhythmias or ischemia
Echocardiography for structural assessment.
Normal Values:
• Heart rate: newborn 110-150, infant 100-150, child 60-120, adolescent 50-100 bpm
PR interval: newborn 0.08-0.12, infant 0.10-0.14, child 0.10-0.16, adolescent 0.12-0.20 seconds
QRS duration: newborn <0.08, infant 0.06-0.08, child 0.06-0.10, adolescent 0.06-0.12 seconds
QTC: all ages 0.35-0.44 seconds (upper limit 0.46).
Interpretation:
• Systematic approach: rate, rhythm, axis, intervals, chamber enlargement, ST-T changes
Use age-appropriate normal values and percentile charts for interpretation
Consider clinical context and correlation with physical examination
Differentiate normal variants from pathological findings using established pediatric ECG criteria and guidelines.
Management/Treatment
Acute Management:
• Life-threatening arrhythmias require immediate intervention: ventricular tachycardia/fibrillation (defibrillation/cardioversion), complete heart block (transcutaneous pacing), SVT (vagal maneuvers, adenosine)
Symptomatic bradycardia may require atropine or pacing
Hemodynamically stable arrhythmias may be observed with continuous monitoring.
Chronic Management:
• Benign variants require reassurance and routine follow-up
Pathological findings require subspecialty cardiology management with treatment individualized based on specific abnormality
Arrhythmias may require antiarrhythmic medications, pacemaker, or ICD placement
Activity restrictions based on underlying condition and risk stratification.
Lifestyle Modifications:
• Activity recommendations based on specific cardiac diagnosis and risk assessment
Athletes with certain ECG abnormalities may require disqualification from competitive sports per established guidelines
Avoidance of QT-prolonging medications in long QT syndrome
Genetic counseling and family screening for inherited conditions.
Follow Up:
• Normal ECGs in asymptomatic children typically require no routine follow-up unless clinical indication develops
Minor abnormalities may require periodic monitoring
Significant abnormalities require cardiology-directed follow-up schedule with repeat ECGs, Holter monitoring, and exercise testing as clinically indicated.
Age-Specific Dosing
Medications:
• Adenosine for SVT: 0.1 mg/kg IV rapid push (max 6 mg first dose), if ineffective give 0.2 mg/kg (max 12 mg)
Amiodarone loading: 5 mg/kg IV over 20-60 minutes, maintenance 5-15 mcg/kg/min
Propranolol: 0.5-1 mg/kg BID-TID
Digoxin: loading 10-15 mcg/kg, maintenance 5-10 mcg/kg/day divided BID.
Formulations:
• Adenosine 6 mg/2 mL vials for IV administration requiring rapid push technique
Amiodarone 50 mg/mL injection and 200 mg tablets
Propranolol 10 mg, 20 mg, 40 mg tablets and 4 mg/mL oral solution
Digoxin 0.25 mg tablets and pediatric elixir 50 mcg/mL for accurate dosing.
Safety Considerations:
• Adenosine causes transient asystole (warn family), contraindicated in second/third-degree heart block or sick sinus syndrome
Amiodarone monitoring for pulmonary, hepatic, and thyroid toxicity
Propranolol monitoring for bronchospasm, hypoglycemia, bradycardia
Digoxin therapeutic levels 1-2 ng/mL, monitor for toxicity.
Monitoring:
• Continuous cardiac monitoring during acute antiarrhythmic therapy
Regular ECGs to assess treatment response and detect proarrhythmic effects
Therapeutic drug levels for digoxin and amiodarone when indicated
Electrolyte monitoring especially potassium and magnesium levels
Liver function and thyroid function with amiodarone therapy.
Prevention & Follow-up
Prevention Strategies:
• Primary prevention through genetic counseling for families with inherited cardiac conditions
Screening of first-degree relatives for long QT syndrome, hypertrophic cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy
Avoidance of QT-prolonging medications in susceptible individuals
Proper hydration and electrolyte balance maintenance.
Vaccination Considerations:
• Standard immunization schedule appropriate for most children with ECG abnormalities unless specific contraindications exist
Myocarditis risk assessment with certain vaccines in high-risk populations
Influenza vaccination especially important for children with underlying cardiac conditions
COVID-19 vaccination recommended with cardiology consultation if concerns.
Follow Up Schedule:
• Normal ECGs: routine follow-up as clinically indicated
Minor abnormalities: annual cardiology follow-up with repeat ECG
Significant abnormalities: cardiology-directed schedule ranging from monthly to annually based on condition severity
Emergency follow-up protocols for symptom development or medication changes.
Monitoring Parameters:
• Clinical symptom assessment at each visit including chest pain, palpitations, syncope, exercise tolerance
Growth and development monitoring especially in children with significant cardiac abnormalities
ECG changes over time with attention to interval measurements and rhythm assessment
Exercise capacity evaluation when appropriate.
Complications
Acute Complications:
• Life-threatening arrhythmias including ventricular tachycardia, ventricular fibrillation, and complete heart block can result in sudden cardiac arrest
Hemodynamically significant SVT can cause heart failure in infants
Drug-induced arrhythmias from antiarrhythmic medications or QT-prolonging drugs
Electrolyte abnormalities causing rhythm disturbances.
Chronic Complications:
• Long-term complications depend on underlying condition: sudden cardiac death in channelopathies and cardiomyopathies, heart failure from chronic arrhythmias, thromboembolic events from atrial fibrillation, pacemaker complications including lead fracture and infection
Activity restrictions impacting quality of life and psychological development.
Warning Signs:
• Symptoms requiring immediate attention include syncope, presyncope, chest pain with exertion, palpitations with hemodynamic compromise, seizures (may be cardiac syncope), or sudden collapse
ECG changes including new arrhythmias, conduction blocks, or ischemic changes warrant urgent evaluation.
Emergency Referral:
• Immediate referral for life-threatening arrhythmias, syncope, chest pain with ECG changes, signs of heart failure, or suspected long QT syndrome with recurrent syncope
Any child with family history of sudden cardiac death and abnormal ECG requires urgent cardiology consultation and risk stratification.
Parent Education Points
Counseling Points:
• Explain age-specific nature of pediatric ECG interpretation and that many findings considered abnormal in adults are normal in children
Discuss specific findings and their clinical significance, emphasizing difference between benign variants and pathological abnormalities
Address activity restrictions and their rationale
Provide information about genetic implications when relevant.
Home Care:
• Monitor for symptoms of cardiac arrhythmias including palpitations, chest pain, shortness of breath, dizziness, or syncope
Maintain adequate hydration and avoid excessive caffeine intake
Ensure compliance with prescribed medications and follow-up appointments
Keep emergency contact information readily available for concerning symptoms.
Medication Administration:
• Give cardiac medications at consistent times with attention to heart rate and blood pressure effects
Use precise measuring devices for liquid medications
Monitor for medication side effects and interactions
Never discontinue cardiac medications abruptly without medical supervision
Store medications safely away from children.
When To Seek Help:
• Seek immediate medical attention for: loss of consciousness or near-fainting episodes, chest pain especially with exertion, severe palpitations or irregular heartbeat, difficulty breathing or chest tightness, seizures, or sudden collapse
Contact cardiologist promptly for: new or worsening symptoms, medication side effects, or concerns about activity restrictions.