Publications by authors named "G A Geffin"
Background: Cold cardioplegic arrest can produce cooling contracture and suboptimal myocardial protection. This study examines whether cooling contracture is associated with maldistribution of cardioplegic solution, particularly subendocardial hypoperfusion, which may impair recovery.
Methods: Canine hearts were arrested by antegrade cold and warm blood cardioplegia in random order.
Background: Warm continuous blood cardioplegia provides excellent protection, but must be interrupted by ischemic intervals to aid visualization. We hypothesized that (1) as ischemia is prolonged, the reduced metabolic rate offered by cooling gives the advantage to hypothermic cardioplegia; and (2) prior cardioplegia mitigates the deleterious effects of normothermic ischemia.
Methods: Isolated cross-perfused canine hearts underwent cardioplegic arrest followed by 45 minutes of global ischemia at 10 degrees C or 37 degrees C, or 45 minutes of normothermic ischemia without prior cardioplegia.
Background: Enhanced recovery after cardioplegic arrest has been observed in rat hearts with hypertrophy induced by hemodynamic overload. We hypothesize that this is related to altered characteristics of hypertrophied myocardium-reflected by increased V(3) isomyosin and glycolytic potential-other than increased left ventricular mass.
Materials And Methods: Isolated hearts from age-matched nonoperated and sham-operated control rats and from aortic-banded, hyperthyroid, and hypothyroid rats-groups in which hypertrophy and V(3) as a percentage of left ventricular myosin vary independently-underwent 2 h of multidose cardioplegic arrest at 8 degrees C followed by reperfusion at 37 degrees C.
Superior recovery of hypertrophied rat myocardium after cardioplegic arrest.
Ann Thorac Surg
February 1998
Background: Although cardioplegic protection of the hypertrophied heart remains a clinical challenge, we have previously observed enhanced recovery in rat hearts with pressure-overload hypertrophy induced by aortic banding. We investigated whether this unexpected result is found in other models of hypertrophy.
Methods: Hearts with hypertrophy induced by aortic banding or administration of desoxycorticosterone acetate were each compared with age-matched sham-operated and nonoperated controls.
Objective: Warm blood cardioplegia requires interruption by ischemic intervals to aid visualization. We evaluated the safety of repeated interruption of warm blood cardioplegia by normothermic ischemic periods of varying durations.
Methods: In three groups of isolated cross-perfused canine hearts, left ventricular function was measured before and for 2 hours of recovery after arrest, which comprised four 15-minute periods of cardioplegia alternating with three ischemic intervals of 15, 20, or 30 minutes (I15, I20, and I30).