Right Ventricular Ejection Fraction During Exercise

The response of right ventricular ejection fraction (RVEF) during exercise and its relationship to the location and extent of coronary artery disease are not fully understood. We have recently developed and validated a new method for scintigraphic evaluation of RVEF using rapid multiple-gated equilibrium scintigraphy and multiple right ventricular regions of interest. The technique has been applied during upright bicycle exercise in 10 normal subjects and 20 patients with coronary artery disease. Resting RVEF was not significantly different between the groups (0.49 ± 0.04 vs 0.47 ± 0.09, respectively, mean ± SD). In all 10 normal subjects RVEF rose (0.49 ± 0.04 to 0.66 ± 0.08, p < 0.01) at peak exercise. At peak exercise in coronary artery disease patients, the group RVEF remained unchanged (0.47 ± 0.09 to 0.50 + 0.11, p = NS), but the individual responses varied. In the coronary artery disease patients, the relationship between RVEF response to exercise and exercise left ventricular function, septal motion and right coronary artery stenosis were studied. Significant statistical association was found only between exercise RVEF and right coronary artery stenosis. RVEF rose during exercise in seven of seven patients without right coronary artery stenosis (0.42 ± 0.06 to 0.58 ± 0.08, p = 0.001) and was unchanged or fell in 12 of 13 patients with right coronary artery stenosis (0.50 + 0.09 to 0.45 i 0.10, p = NS). We conclude that (1) in normal subjects RVEF increases during upright exercise and (2) although RVEF at rest is not necessarily affected by coronary artery disease, failure of RVEF to increase during exercise, in the absence of chronic obstructive pulmonary disease or valvular heart disease, may be related to the presence of significant right coronary artery stenosis. The possibility that severe left ventricular dysfunction in the absence of proximal right coronary artery obstruction may cause abnormal RVEF response to stress requires further evaluation in a larger, more varied patient population.