Low-potassium University of Wisconsin solution for cardioplegia: improved protection of the isolated ischemic neonatal rabbit heart

Recovery of cardiac function and high-energy phosphates following ischemia and reperfusion were determined for hearts perfused with low potassium Univ ersity of Wisconsin solution, high potassium University of Wisconsin soluti on, St Thomas' solution, or subjected to hypothermia alone. Isolated hearts were arrested for either 3 h at 15 degrees C or 6 h at 20 degrees C (n = 7 for each group) with one of the four solutions and then reperfused, Aortic flow after ischemic arrest at 20 degrees C was 40.3 +/- 13.3%, 79.3 +/- 10 .0%, 64.3 +/- 11.9% and 43.9 +/- 15.9% of control values for high potassium University of Wisconsin solution, low potassium University of Wisconsin so lution, St Thomas' solution and hypothermia alone, respectively. Similar re sults were observed in hearts subjected to ischemic arrest at 15 degrees C. Myocardial adenosine triphosphate and creatine phosphate after reperfusion tended to be higher in the low potassium University of Wisconsin solution group. It is concluded that low potassium University of Wisconsin solution may provide reliable cardioplegia during surgery that requires prolonged ca rdiac arrest in neonates and infants. (C) 1999 The International Society fo r Cardiovascular Surgery. Published by Elsevier Science Ltd, All rights res erved.