Changes in myocardial oxygen consumption and coronary sinus blood flow before and after resection of left ventricular aneurysm after myocardial infarction.

The patients in this study consisted of eight men who underwent resection of left ventricular aneurysm. Right and left heart catheterization at rest and measurement of coronary sinus blood flow by continuous thermodilution were performed preoperatively and an average of 6 months after the operation. Coronary sinus blood flow decreased significantly from 161 to 118 ml/min and myocardial oxygen consumption decreased significantly from 17.2 to 10.5 ml/min postoperatively. Cardiac index increased postoperatively. Ejection fraction increased from 0.31 to 0.49 and mean velocity of circumferential fiber shortening significantly increased from 0.53 to 1.0 circ/sec postoperatively. Left ventricular end-diastolic volume decreased significantly from 166 to 120 ml/m2 postoperatively. The mean systolic circumferential tension significantly decreased postoperatively. We believe that the decrease in wall tension postoperatively brought about the reduction in myocardial oxygen consumption. Thus the high wall tension and myocardial oxygen demand, present preoperatively, were improved postoperatively, with a resultant lowering of oxygen consumption and equivalent or better left ventricular function.