Improved detection of posterior myocardial wall ischemia with the 15-lead electrocordiogram

Background A routine 12-lead electrocoidiagram is commonly obtained to eval uate for possible acute myocardiol infarction during the initial screening of patients with chest discomfort Posterior myocardial infarction is common ly missed because it is not usually visible in the standard leads. In this study, we compared the sensitivity and specificity of posterior chest leads (V-7, V-8, and V-9) and 12-leed electrocardiography in detecting posterior injury pattern during single-vessel percutaneous transluminal coronary ang ioplasty. Methods and Results Three posterior chest leads in addition to the routine 12-lead electrocardiogram were monitored simultaneously during single-vesse l percutaneous transluminal coronary angioplasty of the right, circumflex, and left anterior descending coronary arteries in a total of 223 patients. Posterior injury patterns (95%) were detected mostly during circumflex coro nary occlusion. Posterior leads were able to detect injury pattern in 49% ( 36 of 74) of patients, whereas the 12-lead electrocardiogram was able to de tect only 32% (P < .04). When all 15 leads were used to detect all ST eleva tions, sensitivity increased to 57%, with a specificity of 98% for the circ umflex coronary artery. If maximal ST depressions in leads V-2 to V-3 are c onsidered to be from posterior myocardial injury, then the overall sensitiv ity is increased to 69%. Conclusions Posterior leeds significantly increased the detection of poster ior injury pattern compared with the standard 12-lead electrocardiogram. Us ing all 15 leads significantly further improved the detection of circumflex coronary-related injury pattern over the standard 12-lead electrocardiogra m.