ECG is poor in detecting ischemia in areas supplied by which of the following vessels?

The occlusion of posterior descending aery or distal pa of lt circumflex aery lead to posterior wall MI. Posterior MI is diagnosed by placing posterior leads V7 to V9, which are continuation of precordial leads around to the left back. Circumflex aery distribution ischemia is notoriously silent on an ECG as the posterolateral wall is under-represented on a conventional 12 lead ECG Ref: Critical Decisions in Emergency and Acute Care Electrocardiography edited by William J. Brady, Jonathon D. Truwit; Manual of Cardiovascular Medicine By Brian P. Griffin, Page 528