Arrhythmias USMLE Step 1 Practice Question
A 68-year-old man presents for routine evaluation. He reports feeling well with no syncope, palpitations, or dyspnea. Vital signs show BP 138/82 mmHg, HR 72 bpm, RR 16, temperature 37°C, and SpO2 98% on room air. He takes metoprolol for hypertension. ECG reveals a PR interval of 240 milliseconds with each P wave consistently followed by a QRS complex. Chest X-ray shows normal cardiac silhouette. Which diagnosis best explains these findings?
Answer choices
- AFirst-degree AV blockCorrect answer
- BThird-degree AV block
- CSecond-degree AV block, Mobitz II
- DSinoatrial exit block
- ESecond-degree AV block, Mobitz I
- FAtrial flutter with a regular ventricular response
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