Arrhythmias USMLE Step 1 Practice Question
A 74-year-old man with acute inferior wall myocardial infarction develops bradycardia with a heart rate of 38 bpm. Physical exam reveals cannon A waves in the neck. ECG shows P waves marching through QRS complexes at regular intervals, with QRS duration of 0.12 seconds. Which of the following is the most likely diagnosis?
Answer choices
- ASick sinus syndrome
- BSinus bradycardia with bundle branch block
- CThird-degree atrioventricular block with junctional escape rhythmCorrect answer
- DSecond-degree type II atrioventricular block
- EFirst-degree atrioventricular block
- FMobitz I second-degree AV block from acute inferior wall ischemia
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