Assessment of myocardial perfusion with laser Doppler flowmetry. An experimental study on porcine heart.

Laser Doppler flowmetry was applied to the arrested heart of four pigs and to the fibrillating heart of three pigs during cardiopulmonary bypass. The coronary blood flow was maintained during cardiac arrest by infusion of hyperkalemic blood into the aortic root. A significant correlation (r = 0.88, n = 52, p less than 0.001) between laser Doppler signal and coronary blood flow was found during cardiac arrest. During ventricular fibrillation after release of the aortic cross-clamp there was significant correlation (0.84, n = 38, p less than 0.01) between laser Doppler signal and extracorporeal blood flow. A residual laser Doppler signal of about 60% of the maximal value was recorded even after the bypass flow was discontinued. Laser Doppler flowmetry is concluded to permit measurement of myocardial perfusion in the arrested porcine heart. Muscular activity of the heart contributes to the output signal during ventricular fibrillation.