Alternating bundle-branch block in acute coronary syndrome

• Published in: Cor et vasa (English ed.) Vol. 61; no. 1; pp. 68 - 71
• Main Authors: Avsec, Matic, Fister, Misa, Noc, Marko, Radsel, Peter
• Format: Journal Article
• Language: English
• Published: Elsevier Urban & Partner Sp. z o.o 21.03.2019
• Subjects: Acute coronary syndrome; Bundle-branch block; Coronary angiography; Left bundle-branch block; Percutaneous coronary intervention; Right bundle-branch block; Coronary angiography; Percutaneous coronary intervention; Bundle-branch block; Left bundle-branch block; Acute coronary syndrome; Right bundle-branch block
• ISSN: 0010-8650; 1803-7712
• DOI: 10.1016/j.crvasa.2017.12.013

Bundle-branch blocks often blur ischemic ECG changes. Alternating bundle-branch block is not yet fully understood but can hold clinical significance. We present a case of a patient with a known left bundle-branch block (LBBB) who developed a new right bundle-branch block (RBBB) in a setting of acute coronary syndrome. Coronary angiogram revealed subtotal proximal LAD stenosis that was resolved with stent implantation. After the percutaneous coronary intervention RBBB disappeared and LBBB reappeared. The probable reason for the alternating bundle-branch block in the presented case is a new origin of ventricular impulses after initial medical treatment. New onset RBBB has been an intriguing clinical entity often associated with acute myocardial infarction. RBBB could be added to ST-elevation myocardial infarction as an equivalent indication for urgent reperfusion therapy. Why should an emergency physician be aware of this? Alternating bundle-branch block can be an indicator of reperfusion, thus changing the management of an acute coronary syndrome patient.