Correlation of Peak Rate of Myocardial Wall Thickening with Late Postoperative Graft Flows

surgery in the presence of patent or occluded grafts (P > 0.05). Statistically significant increases occurred in the peak rate of systolic wall thickening ofregions supplied by patent bypass grafts, and significant decreases occurred in regions with occluded grafts (P < 0.01). Of 42 preoperatively hypokinetic regions (pdT,/dt > 0 < 5.0 cmls) supplied by a patent graft, 30 improved by an average of 2.6 cm/s after operation; 18 returned to normal. Failure of24 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,/dt = 0) or dyskinetic (pdT,/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 Receivedfor publication 16 December 1975 and in revised form 9 August 1976. 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.