Videometric analysis of regional left ventricular function before and after aortocoronary artery bypass surgery. Correlation of peak rate of myocardial wall thickening with late postoperative graft flows

The peak rate of systolic wall thickening (pdT(w)/dt) in regions of the left ventricle was determined by biplane roentgen videometry in 60 patients before and a median of 14 mo after aortocoronary bypass graft surgery. The left ventricular ejection fraction, stroke volume, and end diastolic volume and pressure did not change significantly after surgery in the presence of patent or occluded grafts (P > 0.05). Statistically significant increases occurred in the peak rate of systolic wall thickening of regions supplied by patent bypass grafts, and significant decreases occurred in regions with occluded grafts (P < 0.01). Of 42 preoperatively hypokinetic regions (pdT(w)/dt>0<5.0 cm/s) supplied by a patent graft, 30 improved by an average of 2.6 cm/s after operation; 18 returned to normal. Failure of 24 hypokinetic regions to improve to normal was associated with myocardial infarction in 11 or with late postoperative graft blood flows of <60 ml/min, measured by videodensitometry, in 10. All seven preoperatively akinetic (pdT(w)/dt=0) or dyskinetic (pdT(w)/dt<0) regions did not improve after the operation despite the fact that, in five of the seven, coronary bypass flows were over 60 ml/min. All eight preoperatively hypokinetic regions supplied by coronary artery graft flows of ≤40 ml/min failed to improve to normal after operation. All nine preoperatively hypokinetic regions supplied by coronary artery graft flows of over 60 ml/min improved to normal after surgery. Late postoperative coronary artery bypass graft flows, the functional status of the myocardium, the status and distribution of the native coronary circulation, and decreased regional function elsewhere in the ventricle must all be considered when regional left ventricular function is interpreted.