Arrhythmias USMLE Step 1 Practice Question
A 29-year-old man from Connecticut presents with lightheadedness and palpitations. Two weeks ago, he had fever (38.9°C), a circular expanding erythema migrans rash on his thigh after camping. Vital signs: BP 98/62, HR 42, RR 16, SpO2 98%. ECG demonstrates complete heart block with normal QRS duration. Serum Lyme serology is positive. He denies recent antibiotic use. Which of the following is the most likely underlying diagnosis?
Answer choices
- ASarcoidosis
- BLyme carditisCorrect answer
- CHyperkalemia
- DRheumatic fever
- EBrugada syndrome
- FAcute myocarditis from enterovirus infection
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.