Optimal potassium concentration in cardioplegic solutions
Yu, G.; Ye, D.
Zhonghua Xin Xue Guan Bing Za Zhi 18(1): 42-6 62
1990
ISSN/ISBN: 0253-3758 PMID: 2397698 Document Number: 361080
A model of perfused cardiac papillary muscle from guinea pig was set up in our lab. The procaine-free St. Thomas' Hospital solution was used as the basic cardioplegic solution. The potassium concentration of the solution was designed by optimization (14.6, 22.8, 28.5, 32.6, 57.8 mmol/L). The papillary muscle was undergone anoxic arrest for 60 min in 32.degree.C. The effect of myocardium preservation was assessed with cardiac action potential, contractility, and terequantitative analysis of ultrastructure. We concluded that; (1) in this research the proper potassium concentration is at the range of 20.7-26.0 mmol/L and the optimal one is 22.8 mmol/L; (2) despite any deviation from the range, phases II and III of the action potential changes first. [K+] .gtoreq. 32.6 mmol/L slows conductivity, weakens contractility and damages the subcellular structure severely; (3) if [K+] is 57.8 mmol/L, anoxic arrest for 60 minutes in 32.degree.C damages of both structure and function of myocardium is irreversible; (4) following the hyperkalemic cardioplegia, there is a secondary change of cardiac action potential in reperfusion period, which shows longer phase II and shorter phase III, smaller Vmax and APA; (5) reperfusion arrhythmia after anoxia hyperkalemic asystole is likely caused by all kinds of conductive disorders resulting from the secondary changes of action potential; (6) arrest time, AT (Y,s) has the negative relativity to the potassium concentration (X, mmol/L) of cardioplegic solution, which can regress to curve 1/Y = 0.10-1.38/X (14.6 .ltoreq. .times. .ltoreq. 57.8). The minimum potassium concentration which can guarantee AT within 30 seconds is 20.7 mmol/L.