Ratio of ST-segment depression in lead V2 to ST-segment elevation in lead aVF in evolving inferior acute myocardial infarction: an aid to the early recognition of right ventricular ischemia.

The potential value of the ratio of precordial ST-segment depression to inferior ST-segment elevation as a sign of concomitant right ventricular (RV) ischemia was examined. The study group consisted of 68 patients, admitted within 3 hours of the onset of inferior acute myocardial infarction (AMI), in whom there was no evidence of prior AMI. In 27 of the 34 patients in whom inferior AMI was the result of right coronary artery occlusion proximal to the RV branch, the magnitude of ST-segment depression in lead V2 was 50% or less of the magnitude of ST-segment elevation in lead aVF, whereas in only 3 of the 34 patients in whom the site of occlusion was either distal to the RV branch (n = 23) or in the left circumflex artery (n = 11) was this ratio 50%; in no patient was it less than 50% (p less than 0.001). All 34 patients with occlusion of the right coronary artery proximal to the RV branch also had regional or global ischemic RV dysfunction by radionuclide ventriculography, with a mean RV ejection fraction of 30 +/- 10% compared with 42 +/- 6% in patients with occlusion distal to the RV branch or in the left circumflex artery (p less than 0.001). In conclusion, in patients with evolving inferior AMI, ST-segment depression in lead V2 of 50% or less of the magnitude of ST-segment elevation in lead aVF may be a useful sign (sensitivity 79%, specificity 91%, positive predictive value 90% and negative predictive value 82%) for identifying patients with concomitant RV ischemia.