Studies of the effects of ventricular fibrillation on the adequacy of regional myocardial flow

This study assesses the effects of ventricular distention during spontaneously and electrically maintained ventricular fibrillation on coronary blood flow distribution, myocardial metabolism, and ventricular performance. Distention of the spontaneously fibrillating, adequately perfused, heart causes a redistribution of left ventricular coronary flow away from the subendocardial region and results in biochemical evidence of ischemia and moderately impaired ventricular function. While electrical fibrillation alone causes these deleterious effects on coronary flow distribution, myocardial metabolism, and performance, distention of the electrically fibrillating heart accentuates the degree of subendocardial underperfusion and metabolic and functional impairment. We conclude that overstretching of muscle fibers by ventricular distention is not the only cause of impaired ventricular function following cardiopulmonary bypass.