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Alternating Bundle Branch Block Despite a Patent Stent in Late-Presenting Extensive Anterior STEMI
Mochamad Y Alsagaff1, Cornelia Ghea1, Hendri Susilo1
1Department of Cardiology and Vascular Medicine, Faculty of Medicine, Universitas Airlangga, Surabaya, East Java, Indonesia; Department of Cardiology and Vascular Medicine, Airlangga University Hospital, Surabaya, East Java, Indonesia.
Background:
Alternating bundle branch block (ABBB) is a rare but high-risk marker of advanced infra-Hisian disease and impending high-grade atrioventricular (AV) block in anterior ST-segment elevation myocardial infarction (STEMI).
Case Summary:
A 39-year-old male smoker presented 19 hours after chest pain onset with extensive anterior STEMI and ABBB. Ostial left anterior descending artery occlusion was treated with overlapping drug-eluting stents, achieving TIMI flow grade III. Despite patent stents, he developed delayed complete AV block. Temporary transvenous pacing restored hemodynamic stability, and AV conduction recovered within 24 hours.
Discussion:
Septal injury, edema, microvascular obstruction, or reperfusion injury can destabilize His-Purkinje conduction despite the presence of open epicardial arteries.
Take-Home Message:
ABBB warrants continuous monitoring and pacing readiness, even when angiography appears reassuring.
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