MacGregor D C, Wilson G J, Tanaka S, Holness D E, Lixfeld W, Silver M D, Rubis L J, Goldstein W, Gunstensen J, Bigelow W G
J Thorac Cardiovasc Surg. 1975 Dec;70(6):945-54.
Ischemic contracture of the left ventricle ("stone heart") is a recognized complication of prolonged periods of interruption of the coronary circulation during open-heart surgery. We have examined the effects of moderate hypothermia (28 degrees C.) and preoperative beta-adrenergic blockade (propranolol, 0.5 mg. per kilogram; 1.0 mg. per kilogram) on contracture development during ischemic arrest of the heart. Four groups of 8 dogs each were placed on total cardiopulmonary bypass, and ischemic arrest of the heart was produced by cross-clamping the ascending aorta and venting the left ventricle. Intramyocardial carbon dioxide tension was continuously monitored by mass spectrometry. When anaerobic energy production ceased, as indicated by a final plateau in the intramyocardial carbon dioxide accumulation curve, the ischemic arrest was terminated and the contractile state of the heart observed. These results are given in the text. We conclude that beta-adrenergic blockade delays, but does not prevent, the onset of ischemic contracture of the left ventricle under normothermic conditions. Moderate hypothermia appears to prevent this complication completely.
左心室缺血性挛缩（“石心”）是心脏直视手术期间冠状动脉循环长时间中断的一种公认并发症。我们研究了中度低温（28摄氏度）和术前β-肾上腺素能阻滞剂（普萘洛尔，每千克0.5毫克；每千克1.0毫克）对心脏缺血停搏期间挛缩发展的影响。将四组每组8只狗置于完全体外循环下，通过夹闭升主动脉和左心室排气造成心脏缺血停搏。通过质谱法连续监测心肌内二氧化碳张力。当心肌内二氧化碳积累曲线出现最终平台表明无氧能量产生停止时，终止缺血停搏并观察心脏的收缩状态。这些结果在文中给出。我们得出结论，在常温条件下，β-肾上腺素能阻滞剂可延迟但不能预防左心室缺血性挛缩的发生。中度低温似乎可完全预防这一并发症。
