Left ventricular function during exercise before and after bypass surgery

Biplane left ventricular cineangiograms and pressure measurements were performed in 44 patients with coronary heart disease at rest and during submaximal or symptom-limited supine bicycle exercise before and 7 +/- 3 months after bypass surgery. Revascularization was complete in 12 (group I) and incomplete in 32 patients (group II). Preoperative left ventricular ejection fraction (EF) was within normal limits at rest and declined similarly during exercise in both groups (group I from 59 to 51%, p less than 0.01; group II from 61 to 48%, p less than 0.001). Postoperative EF at rest was nearly identical to preoperative EF in both groups (group I, 65%; group II, 58%) and remained unchanged during exercise (group I, 63%; group II, 56%). Peak systolic pressure to end-systolic volume index ratio (LVSP/ESVI in mm Hg/ml . m-2) also decreased during exercise in both groups preoperatively (group I from 3.7 to 3.2, NS; group II from 3.4 to 2.6, p less than 0.005). Postoperative LVSP/ESVI at rest was again unchanged as compared to preoperative LVSP/ESVI. During exercise, however, it increased in both groups reaching higher values in patients of group I than of group II (5.1 versus 3.7, p less than 0.05). Whereas both parameters indicate an improvement in global left ventricular function following surgery, LVSP/ESVI even suggests a more sizable recovery of function in patients with complete as compared to those with incomplete revascularization.