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Challenges in Clinical Electrocardiography
September 7, 2021

Do Not Dismiss That Wenckebach

Author Affiliations
  • 1Department of Medicine, University of Florida, Gainesville, Florida
JAMA Intern Med. 2021;181(11):1507-1508. doi:10.1001/jamainternmed.2021.4031

A patient in their mid-70s with a medical history of hypertension and no known history of cardiac disease presented with recurrent syncopal attacks. An electrocardiogram (ECG) showed second-degree Mobitz type 1 (Wenckebach) AV conduction block with right bundle-branch block.

The patient did not show higher levels of AV conduction disease at rest; orthostatic blood pressure and the results of additional routine cardiac evaluation were unremarkable. We decided to assess the patient’s AV conduction response to exercise. In the treadmill stress laboratory, we obtained a standing ECG before the Bruce protocol was initiated (Figure, A) and afterwards at stage 1 of the Bruce protocol (Figure, B).

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1 Comment for this article
Partial Trifascicular block.
H Silverstein, MD | Preventive Medicine Center
I read the resting EKG as also including left anterior hemiblock. Even with first-degree heart block that is partial trifascicular block, on the edge for requiring a pacemaker.