To determine the value of lead V4R for the diagnosis of right ventricular infarction (RVI), the results of radionuclide ventriculography (RVg) were compared with St segment elevation in lead V4R.

12-lead ECG and V4R were recorded in 19 patients with inferior myocardial infarction (MI) when admitted to the coronary care unit. RVg was performed between the 2nd and 5th days after MI. Left and right ventricular ejection fractions and right ventricular free wall motion were assessed. Severe hypokinesia or akinesia of the right ventricular wall was regarded as the marker of RVI. STt segment elevation more than 0,5 mm in lead V4R was considered the ECG criterion for the diagnosis of right ventricular MI.

The sensitivity of V4R for the detection of RVI was found to be rather low (45%), but its specifity was 100%. In the patients with ST segment elevation in V4R, both the right ventricular ejection fraction and wall motion score weree significantly lower (p<0,02) than in the remaining group.

It was concluded that for the diagnosis of RVI, lead V4R is a paremetr with high specificty and low sensitivity. We suggest that lead V4R be recorded in all patients with inferior myocardial infarction and that patients with ST segment elevation in this derivation be managed as right ventricular infarction.