The influence of potassium depletion on cardiac growth response to pressure overload

Previous studies have reported that potassium depletion arrests both body and heart growth, and that aortic ligation can induce myocardial potassium loss. To examine the effects of potassium depletion on the cardiac growth response to an increase in pressure load, we induced severe potassium depletion in rats by dietary means for 3 weeks and then subjected them to aortic ligation. 3 weeks following ligation and after a total of 6 weeks of continued potassium deprivation, the animals were sacrificed. Our results show that after aortic ligation the left ventricular weight in potassium depleted rats significantly increased by an average of 155 mg, a value which was somewhat less than the 208-mg increase observed in normokalemic animals. The presence of focal myocardial necrosis in hypokalemic rats, accordingly, did not appear to prevent the increase in ventricular mass induced by augmented pressure load. Furthermore, despite marked reduction in skeletal muscle potassium content there was no decrease in the myocardial potassium content even after aortic ligation. We conclude that profound dietary potassium depletion for a prolonged period of 6 weeks does not impede the cardiac growth response to an increase in pressure load.