Alcohol and pyruvate cardioplegia. Twenty-four-hour in situ preservation of hamster hearts. Isolated hamster hearts were first perfused with a normal Krebs-Henseleit medium to demonstrate comparable viability of hearts before perfusing and storing them for 24 hours in one of three solutions. The three solutions were a physiologic saline with pyruvate as the substrate and 4% alcohol to arrest the heart (group 1), a standard cardioplegic solution (group 2), and an alcohol-free physiologic saline with pyruvate as the substrate (group 3). Recovery in terms of rate/pressure product and oxygen consumption after 30 minutes of reperfusion was 81% and 93%, respectively, for group 1, 13% and 32% for group 2, and 70% and 72% for group 3. Percent of physiologic recovery was not related to recovery of adenosine triphosphate. The adenosine triphosphate level returned to approximately 40% control level in all three groups, and in all three groups inorganic phosphate remained approximately 320% over control level after 30 minutes of reperfusion. Phosphocreatine level significantly higher in groups 1 and 3 than in group 2, as a result of improved oxygen consumption. Intracellular pH, determined by phosphorous 31 nuclear magnetic resonance spectroscopy, was physiologic in groups 1 and 3 but alkaline in group 2. This alkalinity may have been caused by leaky membranes. Pyruvate helped preserve mitochondrial function during depressed oxygen delivery, such as was seen during the 24-hour storage period. Four percent alcohol arrested the heart; combined with pyruvate plus alcohol solution were better than a standard cardioplegic solution for maintaining functional capability. 