Right ventricular infarction as an independent predictor of prognosis after acute inferior myocardial infarction.

Background: Acute inferior myocardial infarction frequently involves the right ventricle. We hypothesized that right ventricular involvement, as diagnosed by ST-segment elevation in the right precordial lead V4R, may affect the prognosis of patients with inferior myocardial infarctions.

Methods: In 200 consecutive patients admitted to the hospital with acute inferior myocardial infarctions, we assessed the prevalence and diagnostic accuracy of ST-segment elevation in lead V4R (as compared with four other diagnostic procedures) to identify right ventricular involvement and its prognostic implications for in-hospital and long-term outcomes.

Results: The in-hospital mortality after inferior myocardial infarction was 19 percent, and major complications occurred in 47 percent of the patients. The presence of ST-segment elevation in lead V4R in 107 patients (54 percent) was highly predictive of right ventricular infarction (sensitivity, 88 percent; specificity, 78 percent; diagnostic accuracy, 83 percent), as compared with the other diagnostic procedures. The patients with ST-segment elevation in lead V4R had a higher in-hospital mortality rate (31 percent vs. 6 percent, P < 0.001) and a higher incidence of major in-hospital complications (64 percent vs. 28 percent, P < 0.001) than did those without ST-elevation in V4R. Multiple logistic-regression analysis showed ST elevation in V4R to be independent of and superior to all other clinical variables available on admission for the prediction of in-hospital mortality (relative risk, 7.7; 95 percent confidence interval, 2.6 to 23) and major complications (relative risk, 4.7; 95 percent confidence interval, 2.4 to 9). The post-hospital course (follow-up, at least 1 year; mean follow-up, 37 months) was similar in patients with and in those without electrocardiographic evidence of right ventricular infarction.

Conclusions: Right ventricular involvement during acute inferior myocardial infarction can be accurately diagnosed by the presence of ST-segment elevation in lead V4R, a finding that is a strong, independent predictor of major complications and in-hospital mortality. Electrocardiographic assessment of right ventricular infarction should be routinely performed in all patients with acute inferior myocardial infarctions.