Medical College of Wisconsin
CTSICores SearchResearch InformaticsREDCap

Calcium content of St. Thomas' II cardioplegic solution damages ischemic immature myocardium. Ann Thorac Surg 1991 Oct;52(4):993-9



Pubmed ID




Scopus ID

2-s2.0-0025945370   23 Citations


Clinical application of hypothermic pharmacologic cardioplegia in pediatric cardiac surgery is less than satisfactory, despite its well known benefits in adults. Protection of the ischemic immature rabbit heart with hypothermia alone is better than with hypothermic St. Thomas' II cardioplegic solution. Control of cellular calcium is a critical component of cardioplegic protection. We determined whether the existing calcium content of St. Thomas' II solution (1.2 mmol/L) is responsible for suboptimal protection of the ischemic immature rabbit heart. Modified hypothermic St. Thomas' II solutions (calcium content, 0 to 2.4 mmol/L) were compared with hypothermic Krebs bicarbonate buffer in protecting ischemic immature (7- to 10-day-old) hearts. Hearts (n = 6 per group) underwent aerobic "working" perfusion with Krebs buffer, and cardiac function was measured. The hearts were then arrested with a 3-minute infusion of either cold (14 degrees C) Krebs buffer (1.8 mmol calcium/L) as hypothermia alone or cold St. Thomas' II solution before 6 hours of hypothermic (14 degrees C) global ischemia. Hearts were reperfused, and postischemic enzyme leakage and recovery of function were measured. A bell-shaped dose-response profile for calcium was observed for recovery of aortic flow but not for creatine kinase leakage, with improved protection at lower calcium concentrations. Optimal myocardial protection occurred at a calcium content of 0.3 mmol/L, which was better than with hypothermia alone and standard St. Thomas' II solution. We conclude that the existing calcium content of St. Thomas' II solution is responsible, in part, for its damaging effect on the ischemic immature rabbit heart.

Author List

Baker EJ 5th, Olinger GN, Baker JE


John E. Baker PhD Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Age Factors
Calcium Chloride
Cardioplegic Solutions
Creatine Kinase
Hypothermia, Induced
Potassium Chloride
Sodium Chloride
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a