ECG Patterns
You’re handed an ECG of a 10-year-old boy who presented with palpitations. You notice a short PR interval, delta wave, and slurred upstroke to the QRS. What’s the diagnosis?
Wolff-Parkinson-White (WPW) Syndrome
Caused by an accessory pathway (the bundle of Kent) bypassing the AV node. This pre-excites the ventricles, producing the characteristic delta wave and short PR interval. Risk includes re-entrant SVT or rapid conduction during atrial fibrillation, potentially leading to ventricular fibrillation. Avoid AV nodal blockers like adenosine or beta blockers in wide-complex irregular rhythms.
A 9-year-old faints while standing. She’s pale but recovers quickly. ECG is normal. Likely diagnosis?
Vasovagal Syncope
Most common cause of syncope in pediatrics. Triggered by prolonged standing, heat, or stress. Key findings: prodrome (nausea, lightheadedness), rapid recovery. ECG still necessary to rule out cardiac causes.
A 15-year-old collapses in his sleep. ECG shows a coved ST segment in V1-V2. Diagnosis?
Brugada Syndrome
Sudden nocturnal death is a red flag. Consider EP evaluation and ICD. Avoid sodium channel blockers.
A 2-month-old is brought in for bradycardia. Mother has lupus. ECG shows AV dissociation. What’s the rhythm?
Complete (3rd-degree) heart block — Maternal anti-Ro/SSA antibodies damage fetal conduction tissue. Neonates may require pacing.
A toddler presents with tachypnea and irritability one week after a virus. ECG shows low voltage. What’s the likely diagnosis?
Myocarditis
Often viral (e.g., Coxsackie). Can cause arrhythmias or cardiogenic shock. Workup includes troponin, BNP, echo. Admit to PICU.
An ECG shows a short PR interval and slurred QRS upstroke. What is the name of the accessory pathway responsible?
The Kent Bundle
This tract directly connects the atria and ventricles, bypassing the AV node. Its presence defines WPW syndrome and can facilitate dangerous arrhythmias if atrial fibrillation occurs.
You’re asked what test to order in all kids with unexplained syncope. What’s your answer?
12-lead ECG
First-line screen for arrhythmias, Long QT, WPW, Brugada, and HCM. Always include with any unexplained or exertional syncope in pediatrics.
A 14-year-old collapses at swim practice. QTc is 500 ms. What’s the most likely diagnosis?
LQT1
Triggered by exertion, especially swimming. Risk of torsades. Treat with beta blockers and restrict activity.
A cyanotic newborn has a boot-shaped heart on X-ray. What congenital lesion is likely?
Tetralogy of Fallot — Four components: RV outflow obstruction, VSD, overriding aorta, RVH. Cyanotic spells (tet spells) require oxygen, squatting, or surgery.
A child is hypotensive with muffled heart sounds and distended neck veins. ECG shows electrical alternans. What’s the diagnosis?
A child is hypotensive with muffled heart sounds and distended neck veins. ECG shows electrical alternans. What’s the diagnosis?
A febrile child has an ECG showing a Brugada Type 1 pattern. ECG normalizes when the fever resolves. What’s channel is affected?
Brugada Syndrome — A sodium channelopathy that can be unmasked by fever. Type 1 ECG shows coved ST elevations in V1–V2 with T-wave inversion. Fever may provoke fatal arrhythmias. Antipyretics are essential; high-risk patients may need an ICD.
A 14-year-old collapses during emotional stress. ECG is normal at rest, but stress test shows bidirectional VT. What condition does this suggest?
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
Channelopathy triggered by adrenergic surge. ECG at rest is normal; exercise or emotion triggers polymorphic or bidirectional VT. Treat with beta blockers and avoid exertion.
A 12-year-old collapses during emotional stress. Stress testing reveals bidirectional VT. What is this?
Catecholaminergic Polymorphic Ventricular Tachycardia
Look for polymorphic or bidirectional VT during exercise. Normal ECG at baseline. Requires beta blockers or flecainide. High-risk patients may need ICD.
During a "tet spell," what is immediate therapy?
What is knee-to-chest position, sodium bicarbonate, morphine, and oxygen. Surgery is not an immediate treatment!
A one year old presents to the clinic in SVT. What is the most common method used to try and convert out of SVT in this scenario
What is bag of ice on the face?
A teenager collapses after sprinting. ECG shows QTc 510 ms and notched T waves. What inherited syndrome should you suspect?
Long QT Syndrome (LQTS) — Likely LQT1 subtype if triggered by exercise. Prolonged ventricular repolarization predisposes to torsades de pointes. QTc >480 ms is diagnostic. Treat with beta blockers and avoid QT-prolonging medications. Genetic testing and family screening are key.
A teen faints after a loud buzzer startles her. QTc is prolonged. What arrhythmia subtype is most likely?
LQT2
Startle-induced events and T-wave notching point toward this subtype. Estrogen-sensitive, often in adolescent girls. Beta blockers are first-line, but high-risk patients may require ICD.
A teen in SVT has irregular wide-complex tachycardia. Why avoid AV nodal blockers?
AV nodal blockers (e.g., adenosine, beta blockers) can worsen WPW with atrial fibrillation — may precipitate ventricular fibrillation. Use procainamide or perform cardioversion.
A 6-month-old presents with CHF signs. ECG shows biventricular hypertrophy. What is the likely lesion?
Large VSD
High flow left-to-right shunt increases pulmonary pressures, leading to heart failure. Surgical closure often needed.
A teen athlete has palpitations and syncope. ECG shows epsilon wave in V1. What diagnosis should you suspect?
ARVC
Arrhythmogenic right ventricular cardiomyopathy. Risk of sudden death. Refer for EP and possible ICD.
A 5-year-old presents with fever and chest pain. ECG shows diffuse ST elevations and PR depressions. What is the diagnosis?
Pericarditis — Viral or autoimmune inflammation of the pericardium. ECG shows diffuse ST elevation (concave up) and PR depression. Look for pericardial effusion on ultrasound. NSAIDs and colchicine are first-line; monitor for tamponade.
A 16-year-old collapses during basketball. A murmur is heard. ECG shows high voltage. What condition is likely?
Hypertrophic Cardiomyopathy (HCM)
Common cause of sudden death in athletes. ECG may show LVH, deep Q waves. Echo confirms diagnosis. Murmur increases with Valsalva.
A 10-year-old boy has QTc 455 ms. What’s the upper limit of normal QTc in boys?
QTc >460 ms in boys or >470 ms in girls is abnormal. Evaluate symptoms, family history, and medications.
A 4-day-old term infant presents with poor feeding, lethargy, and mottled skin. Pulses are weak and femoral pulses are diminished. ECG shows LVH. What congenital lesion should be high on your differential?
What is Coarctation of the Aorta?
➡️ Coarctation is a narrowing of the aortic arch, typically just distal to the left subclavian artery. In neonates, closure of the ductus arteriosus may lead to acute decompensation. Signs include poor perfusion, weak femoral pulses, and metabolic acidosis. ECG may show left ventricular hypertrophy due to increased afterload. Prostaglandin E1 is critical to maintain ductal patency. Confirm with echocardiogram; surgical repair is definitive.
A 7-year-old girl is brought in after collapsing at recess. She was pulseless and required CPR. ECG post-ROSC reveals deeply inverted T waves in V1–V3. Echocardiogram shows severely dilated left ventricle with decreased systolic function. What is the likely diagnosis?
What is Dilated Cardiomyopathy (DCM)?
DCM in children can present with arrhythmia, heart failure, or sudden cardiac arrest. It may be idiopathic, post-viral, genetic, or related to toxins/metabolic disease. ECG may show nonspecific ST/T changes or ventricular arrhythmias. Echo confirms LV dilation and reduced function. Management includes stabilization (diuretics, inotropes), arrhythmia suppression, and referral for advanced heart failure therapy. Consider myocarditis or familial DCM in workup.