RIGHT VENTRICULAR EJECTION FRACTION DURING EXERCISE IN PATIENTS WITH CORONARY-ARTERY DISEASE

The effect of the location of right coronary artery (RCA) lesions upon right ventricular ejection fraction (RVEF) during exercise was investigated using first-pass radionuclide angiography. Thirty-seven patients were studied at rest and during upright bicycle exercise: 11 controls (group 1) and 26 patients with significant (> 70%) coronary artery stenosis, divided into those without lesions of the RCA proximal to the acute margin (group 2, n = 14) and those with proximal RCA lesions (group 3, n = 12). In group 1, left ventricular ejection fraction (LVEF) increased from 0.68 ± 0.07 (SD) at rest to 0.76 ± 0.06 during exercise (p < 0.01), and RVEF increased from 0.47 ± 0.04 to 0.57 ± 0.06 (p < 0.01). In group 2, LVEF fell from 0.63 ± 0.13 to 0.58 ± 0.11 during exercise (p < 0.01), while RVEF increased from 0.49 ± 0.06 to 0.58 ± 0.09 (p < 0.01). The LVEF response to exercise in group 2 was significantly different from that in group 1 (p < 0.01); the RVEF response did not differ significantly. When group 2 was subdivided into patients without RCA lesions and those with distal RCA lesions, there was no significant difference in the RVEF response to exercise. In group 3, LVEF fell from 0.53 ± 0.17 at rest to 0.45 ± 0.14 during exercise (p < 0.01), while RVEF did not change significantly (0.50 ± 0.07 at rest and 0.46 ± 0.10 during exercise). In LVEF response to exercise in group 3 was not significantly different from that in group 2; however, the RVEF response differed significantly from that in groups 1 and 2 (p < 0.01). Proximal RCA lesions are associated with a fall in LVEF and no change in RVEF during exercise, while coronary artery disease that does not involve the proximal RCA results in a fall in LVEF and a rise in RVEF. Thus, there can be a dissociation of the exercise response of the right and left ventricles, determined by the location of coronary artery lesions.