Coronary Artery Disease USMLE Step 1 Practice Question
A 71-year-old man presents after two episodes of syncope. Vital signs: BP 98/62, HR 42, RR 16, SpO2 98% on room air. He denies chest pain or dyspnea. Electrocardiogram shows a constant PR interval with intermittent nonconducted P waves and wide QRS complexes. Troponin is normal. Which of the following best describes this conduction abnormality?
Answer choices
- ABlock within the atrioventricular node that is usually benign
- BInfranodal conduction disease with risk of progression to complete heart blockCorrect answer
- CReentrant rhythm within the AV node
- DAccessory pathway between the atria and ventricles
- EEnhanced phase 4 depolarization in Purkinje tissue
- FSinoatrial node dysfunction with abnormal automaticity
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