Distribution of adenylates, water, potassium, and sodium within the normal and hypertrophied canine heart following 2 hr of preservation

Abstract

The hypertrophied heart is more susceptible to ischemic damage than the normal heart, and undergoes larger changes in water and electrolyte content during the reperfusion period. Therefore, we studied in vivo the effects of 2 hr of ischemic preservation at 12°C using electrolyte (CC) or blood cardioplegia (BC) on water and electrolyte content and on high-energy phosphate levels in the normal (N) and hypertrophied (H) canine heart. A control group of dogs (CP) was placed on cardiopulmonary bypass for 4 hr. Hypertrophied hearts were studied 4 to 6 months following supraaortic banding in puppies. ATP, extracellular space (ECS), tissue sodium (Na), tissue potassium (K), and water volume ( VH 2O) were measured in full width myocardial biopsies taken at 1 2 and 2 hr of reperfusion. There was no difference in these measurements between hearts preserved with BC or CC, but there were significant differences between normal and hypertrophied hearts. At 1 2 hr, in hypertrophied hearts ECS was 50% greater, NA 40% greater, and VH 2O 12% greater than previously determined normal values in our laboratory. In normal hearts at 1 2 hr there was only a 15% increase in ECS, 14% increase in Na, and 5% increase in VH 2O. When comparing normal and hypertrophied hearts, only the differences in Na accumulation and ECS were statistically significant. All values were normal at 2 hr. Normal and hypertrophied hearts maintained baseline levels of ATP at the end of preservation and throughout the reperfusion period. Although both the hypertrophied and normal heart accumulated H 2O and Na early in the reperfusion period, these changes returned to normal at 2 hr and were not associated with disruption of cellular energy levels.