Site Search     
Proceedings Logo
Past Issue:
Volume 13, Number 3 • July 2000		  
Arrow Bullet Return to Table of Contents


BUMC Proceedings 2000;13:293-294

Which is the culprit artery?
white box.gif (46 bytes)
D. LUKE GLANCY, MD, ROBERT S. LEWIS, MD, RADHAKRISHNAN NAIR, MD, DOUGLAS MENDOZA, MD, AND FAROUK BELAL, MD

From the Section of Cardiology, Department of Medicine, Louisiana State University Health Sciences Center and The Medical Center of Louisiana, New Orleans.

Corresponding author: D. Luke Glancy, MD, Section of Cardiology, Department of Medicine, Louisiana State University Medical Center, 1542 Tulane Avenue, New Orleans, Louisiana 70112..

white box.gif (46 bytes)
 
59-year-old woman had been treated at another hospital for unstable angina for 5 days. One day after discharge, she returned with prolonged chest pain, and an electrocardiogram was recorded (Figure 1).

The most notable features of the electrocardiogram are ST and T changes in leads V1 through V4. Superficially, these changes suggest a left anterior descending lesion with anterior subendocardial ischemia and/or injury, but closer inspection indicates otherwise. Minimal ST-segment elevation and slight terminal T-wave inversion are seen in lead III, and the reciprocal of these changes is noted in aVL, where ST depression and a negative/positive diphasic T wave are apparent. Thus, there is evidence of transmural inferior injury (1). A second look at V2 through V4 suggests ST depression and negative/positive diphasic T waves similar to those seen in aVL, implying that these changes are reciprocal to ST elevation and slight terminal T-wave inversion over the posterior wall of the left ventricle. Thus, the electrocardiogram indicates not anterior but posterior and inferior transmural injury.

Either right or left circumflex coronary artery occlusion can produce posterior and inferior injury. Because the ST and T changes are most marked in V1 through V4and because these changes are typical of left circumflex occlusion, that seems the likely culprit (2, 3). The ST is depressed in aVL, suggesting that the lesion is distal to the first obtuse marginal branch. Angiograms made 4 days later at The Medical Center of Louisiana in New Orleans show complete occlusion of the left circumflex distal to 2 obtuse marginal branches (Figure 2). The right coronary artery is narrowed proximally, but the left circumflex is the culprit.

  1. Birnbaum Y, Sclarovsky S, Mager A, Strasberg B, Rechavia E. ST segment depression in aVL: a sensitive marker for acute inferior myocardial infarction. Eur Heart J 1993;14:4-7.
  2. Shah A, Wagner GS, Green CL, Crater SW, Sawchak ST, Wildermann NM, Mark DB, Waugh RA, Krucoff MW. Electrocardiographic differentiation of the ST-segment depression of acute myocardial injury due to the left circumflex artery occlusion from that of myocardial ischemia of nonocclusive etiologies. Am J Cardiol 1997;80:512-513.
  3. Sclarovsky S, Topaz O, Rechavia E, Strasberg B, Agmon J. Ischemic ST segment depression in leads V2-V3 as the presenting electrocardiographic feature of posterolateral wall myocardial infarction. Am Heart J 1987;113:1085-1090.