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December 12, 1980

Fascicular Block and Acute Myocardial Infarction

Author Affiliations

From the Department of Medicine, University of California, San Francisco.

JAMA. 1980;244(23):2646-2649. doi:10.1001/jama.1980.03310230046027

PROPER treatment of patients with acute myocardial infarction and fascicular block depends on understanding of the relationship between the ventricular specialized conduction system and its blood supply. In this article, we detail the importance of site of infarction, the type of ECG abnormality, and the clinical status of the patient in formulating a rational treatment program.

VENTRICULAR SPECIALIZED CONDUCTION SYSTEM (VSCS) AND ITS BLOOD SUPPLY  The VSCS begins with the branching portion of the His bundle in which fibers segregate into right and left bundle branches (Fig 1). The right bundle-branch (RBB) is long and slender and terminates into a Purkinje network relatively late in its course. In contrast, the left bundle-branch (LBB) divides early into a left anterior fascicle and a left posterior fascicle.1 Special fibers derived from the left conducting system activate the septum. The blood supply to the His bundle is usually dual,2 arising from