Experimental evaluation of myocardial preservation techniques: V. A. membrane-stabilizing agent, procaine...

The protective effects of procaine hydrochloride on the anoxic heart were investigated using the papillary muscle contractility of an isolated, blood-perfused rabbit heart as an index of myocardial function. Fifty-four experiments were divided into nine groups of six experiments each, in which anoxic periods (30, 45, 60 minutes) and concentration of procaine (solution 3, 0.3%) were the variables. The hearts arrested significantly faster with solution 3 compared with solution 2 or 1 (p < 0.01). After 30 minutes of anoxia, the recovery of the contractility was 81.1 +/- 4.2% with solution 1, 90.7 +/- 3.4% with solution 2, and 90.6 +/- 3.3% with solution 3. After 45 minutes of anoxia, the recovery was 31.8 +/- 19.0% with control, 67.5 +/- 15.8% with 0.03% procaine, and 58.1 +/- 22.8% with 0.3% procaine. After 60 minutes of anoxia, the recovery was 2.2 +/- 2.7% with control, 18.7 +/- 14.1% with 0.03% procaine, and 5.0 +/- 7.3% with 0.3% procaine. After each anoxic period, the best recovery occurred with those hearts arrested by solution 2. Although the difference in recovery between the procaine groups was not statistically significant, a longer time was required for the hearts arrested with solution 3 to reach full functional recovery. This study indicated that procaine per se has a protective effect on the anoxic hearts and that although high concentration (0.3%) of procaine arrests the heart rapidly, it delays the recovery of contractions. We recommend the use of 0.03% procaine in cardioplegic solution.