Significance of exercise-induced ST-segment deviation in right-sided chest leads in the diagnosis of right ventricular ischemia.
Seventy-three patients were subjected to bicycle ergometry and exercise-induced ST-segment changes in right-sided chest leads were correlated with changes in conventional leads. ST-segment elevation in right-sided chest leads was found to be more frequent than ST-segment depression. ST-segment elevation in right-sided chest leads was commonly reciprocal to ST-segment depression in leads V3 to V7, indicating that this change is usually secondary to left ventricular subendocardial ischemia, rather than to right ventricular ischemia. ST-segment depression in right-sided chest leads was mostly a primary change indicating right ventricular subendocardial or posterior wall ischemia. It is, therefore, felt that ST-segment depression in right-sided chest leads is more sensitive and specific for right ventricular ischemia than ST-segment elevation in these leads.