Arrhythmias USMLE Step 1 Practice Question
A 73-year-old man with hypertension presents with two episodes of unexplained syncope over three months. Vital signs: BP 148/92 mmHg, HR 58 bpm, RR 16, temp 37°C, SpO2 98% on room air. ECG demonstrates right bundle branch block with left anterior fascicular block. Troponin is normal. He denies palpitations or chest pain. He takes lisinopril and metoprolol. Which conduction abnormality best explains the clinical significance of these findings?
Answer choices
- AIt is the expected pattern of an athletic heart
- BIt proves the patient has Wolff-Parkinson-White syndrome
- CIt confirms acute pericarditis
- DIt indicates disease in two fascicles of the His-Purkinje system and risk of progression to complete heart blockCorrect answer
- EIt reflects isolated AV nodal disease with no prognostic value
- FIt demonstrates normal age-related degenerative changes requiring only observation and lifestyle modification
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