COMPARISON OF DIAGNOSTIC-ACCURACY, TIME DEPENDENCY, AND PROGNOSTIC IMPACT OF ABNORMAL Q-WAVES, COMBINED ELECTROCARDIOGRAPHIC CRITERIA, AND ST SEGMENT ABNORMALITIES IN RIGHT-VENTRICULAR INFARCTION

Objective-To determine the diagnostic and prognostic impact of abnorma l Q waves in comparison to or in combination with ST segment abnormali ties in the right precordial and inferior leads as indicators of right ventricular infarction during the acute phase of inferior myocardial infarction. Design-Prospective study of a consecutive series of 200 pa tients with acute inferior myocardial infarction with and without righ t ventricular infarction. Setting-Department of internal medicine, uni versity clinic. Results-Right ventricular infarction was diagnosed in 106 (57%) out of 187 patients from the results of coronary angiography , technetium pyrophosphate scanning, and measurement of haemodynamic v ariables or at necropsy, or both. In the acute phase of inferior infar ction ST segment elevation greater than or equal to 0.1 mV in any of t he right precordial leads V4-6R was the most reliable criterion for ri ght ventricular infarction (sensitivity, 89%; specificity, 83%). Abnor mal Q waves in the right precordial leads, the most specific criterion (91%) for right ventricular infarction, were superior to ST segment e levation in patients admitted >12 hours after the onset of symptoms. B oth ST segment elevation in leads V4-6R (increase in in hospital morta lity, 6.2-times; P < 0.001; major complications, 2.3-times; P < 0.01) and abnormal Q waves (2.3-times, P < 0.05; 1.8-times, P < 0.05) on adm ission were highly predictive of a worse outcome during the in hospita l period. In the presence of inferior myocardial infarction previously proposed combined electrocardiographic criteria were not better diagn ostically or prognostically than ST segment abnormalities and abnormal Q waves alone. Conclusions-During the first 24 hours of inferior myoc ardial infarction ST segment elevation and abnormal Q waves derived fr om the right precordial leads are complementary rather than competitiv e criteria for reliably diagnosing right ventricular infarction, both indicating a worse in hospital course for the patient. In this they ar e better than any other previously proposed combined electrocardiograp hic criteria in diagnosing right ventricular infarction. Right precord ial leads should be routinely monitored in acute inferior myocardial i nfarction.