GLOBAL-ISCHEMIA IN THE IMMATURE CANINE VENTRICLE - ENHANCED PROTECTIVE EFFECT OF VERAPAMIL AND POTASSIUM

  • 1 January 1984
    • journal article
    • research article
    • Vol. 87  (2) , 213-219
Abstract
The efficacy of the addition of verapamil to a cardiopleagic solution was evaluated in immature canine hearts subjected to normothermic global ischemia. Two groups of mongrel puppies < 10 wk old were subjected to 30 min of global myocardial ischemia while on cardiopulmonary bypass. One group (group K) was arrested with cardioplegic solution containing 20 meq/l of KCl; the other group (group K + V) was arrested with the same solution containing 0.2 mg/kg of verapamil. Ultrasonic crystals were placed for measurement of left ventricular dimensions, and micromanometers measured left ventricular pressures. Functional measurements included left ventricular strain, 1st derivative of left ventricular pressure (dP/dt), and the end-systolic pressure/volume ratio (Emax). Metabolic recovery was assessed by measuring myocardial ATP content. Ninety minutes following ischemia, group K + V exhibited greater minor axis strain at a left ventricular end-diastolic pressure of 15 and 20 mm Hg (P < 0.05), greater dP/dt (P < 0.05-0.001), and greater Emax (P < 0.05) than group K. ATP content in group K + V was greater at 60 min (group K + V: 12.74 .+-. 1.60 .mu.mol/g; group K: 8.39 .+-. 1.30, P < 0.05) and 90 min (group K + V: 10.34 .+-. 0.46; group K: 7.55 .+-. 1.42, P < 0.05) after ischemia. The addition of verapamil to a cardioplegic solution containing K enhances the recovery of function and high-energy phosphate stores in the immature myocardium following normothermic global ischemia.