Myocardial energy substances in the dog heart during potassium and hypothermic arrest

Abstract

Canine hearts were arrested with potassium citrate at 37 C and with cold blood at 17 C. Biopsies were taken from the nonperfused hearts at 0, 5, 20, and 60 min and analyzed by specific microtechniques for AMP, ADP, ATP, phosphocreatine, inorganic phosphate, glycogen, lactic acid, and pyruvic acid. During potassium citrate arrest at 37 C the ATP level was reduced 4.41 mmoles/kg to an average value of .77 mmoles/kg. During hypothermic arrest the ATP level decreased only 1.88 mmoles/ kg. Arrested hearts at 37 C utilized four times as much glycogen and produced three times as much lactic acid as hearts at 17 C. Phosphocreatine fell to low values in both types of arrest within 20 min. The levels of AMP, ADP, and pyruvic acid remained fairly constant throughout the period of arrest. It appears from this data and earlier human biopsy data that selective hypothermic arrest is tolerated far better than potassium citrate arrest. Submitted on September 18, 1961