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Challenges in Clinical Electrocardiography
March 2016

Wenckebach—Second-Degree Heart Block and the Company It Keeps

Author Affiliations
  • 1Electrophysiology Section, Division of Cardiology, University of California, San Francisco

Copyright 2016 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.

JAMA Intern Med. 2016;176(3):382-385. doi:10.1001/jamainternmed.2015.7592

A man in his 70s with hypertension, coronary artery disease (CAD), and right coronary (RCA) stent placement 2 months prior for unstable angina presented to the emergency department after an episode of presyncope, a sense of chest tightness, and palpitations. He had a history of left bundle branch block (LBBB) on electrocardiography (ECG). His medications included carvedilol, aspirin, clopidogrel, and lovastatin. In the emergency department, his ECG showed first-degree heart block and LBBB, and telemetry showed atrioventricular (AV) Wenckebach (ie, Mobitz type 1) heart block (Figure 1). Periods of 2:1 AV block were also captured (Figure 2). A subsequent echocardiogram showed left ventricular hypertrophy but was otherwise normal. Cardiac catheterization demonstrated the recent RCA stent and a chronic left anterior descending (LAD) stent to be patent. Without an ischemic etiology for his symptoms, and noting his cardiac conduction disease, the emergency department referred the patient for electrophysiology study (EPS) (Figure 3).

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