ACUTE POSTERIOR WALL MYOCARDIAL-INFARCTION - ELECTROCARDIOGRAPHIC MANIFESTATIONS

Myocardial infarction (MI) of the posterior wall of the left ventricle involves occlusion of either the left circumflex or the right coronar y artery. Posterior wall MI most often occurs along with acute inferio r or lateral MI; isolated posterior wall MI, however, does occur, Elec trocardiographic abnormalities suggestive of acute posterior wall MI i nclude the following (in leads V-1, V-2, or V-3): (1) horizontal ST se gment depression; (2) a tall, upright T wave; (3) a tall, wide R wave; and (4) an WS wave ratio greater than 1.0 (in lead V-2 only), Further , the combination of horizontal ST segment depression with an upright T wave increases the diagnostic accuracy of these two separate electro cardiographic findings. The additional-lead electrocardiogram using le ft posterior thorax leads is potentially helpful; ST segment elevation greater than 1 mm in this distribution suggests an acute posterior wa ll MI. (Am J Emerg Med 1998;16:409-413 Copyright (C) 1998 by W.B. Saun ders Company).