Arrhythmias USMLE Step 1 Practice Question
A 12-year-old boy presents with syncope during soccer practice. Vital signs show BP 110/68 mmHg, HR 82 bpm, RR 16/min, temperature 37°C, and SpO2 98% on room air. Resting ECG and transthoracic echocardiography are normal. Exercise stress testing induces bidirectional and polymorphic ventricular tachycardia with exercise cessation terminating arrhythmias. Serum electrolytes including potassium and magnesium are normal. Which of the following is the most likely diagnosis?
Answer choices
- AAtrial flutter
- BLong QT syndrome
- CBrugada syndrome
- DAV nodal reentrant tachycardia
- ECatecholaminergic polymorphic ventricular tachycardiaCorrect answer
- FHypertrophic cardiomyopathy
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