Arrhythmias USMLE Step 1 Practice Question
A 45-year-old man with no prior cardiac history reports intermittent palpitations and sensation of skipped beats, particularly after inadequate sleep. Vital signs: BP 128/82 mmHg, HR 76 bpm, RR 14/min, temp 37°C, SpO2 98% on room air. Physical examination reveals regular rate and rhythm with no murmurs. ECG demonstrates occasional wide QRS complexes (>120 ms) without preceding P waves, followed by full compensatory pauses. Troponin is normal. Which diagnosis best explains these findings?
Answer choices
- APremature ventricular contractionsCorrect answer
- BAccelerated idioventricular rhythm
- CFirst-degree AV block
- DPremature atrial contractions
- EAtrial fibrillation
- FWolff-Parkinson-White syndrome
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