Significance of R wave changes in exercise-induced supraventricular extrasystoles: Angiographic correlates

Abstract

The evaluate the clinical significance of observed R wave amplitude changes in exercise-induced supraventricular extrasystoles in comparison to the preceding sinus beat, 94 patients catheterized for possible coronary artery disease (CAD) were studied. Significant CAD was documented in 63 patients—34 with myocardial infarction (group A 1) and 29 without (group A 2)—whereas 31 patients had normal coronary arteries or coronary lesions less than 30% (group B). All patients underwent treadmill stress testing using the Bruce protocol within a month after cardiac catheterization. R wave amplitude increased or remain unchanged in extrasystole (R(x − s) ≥0) in patients with CAD, while it decreased (negative R(x − s) in patients without significant CAD ( P < .0001). In patients with CAD R(x − s) values were positively related to the number of obstructed coronary arteries ( P < .01), while no significant difference was found between groups A 1 and A 2. The correlations of R wave amplitude changes in extrasystoles were significant with coronary obstruction score values (r = .82 and .85 in groups A 1 and A 2, respectively) and with left ventricular ejection fraction values (r = − .88, − .86 and − .90 in groups A 1, A 2, and B, respectively). R(x − s) ≥0 value had a sensitivity of 79% and a specificity of 90% for CAD detection, while sensitivity was higher (89%) and specificity was lower (57%) for the prediction of left ventricular dysfunction. It is concluded that R(x − s) ≥0 value is indicative of CAD, multivessel disease, and poor left ventricular performance, while its negative value is combined with minimal or no CAD and normal ejection fraction values.