Ultrastructural study of the myocardium using cardioplegic crystalloid solution with and without procaine in patients undergoing aortic valve replacement.

Objective: The aim of this study was to assess whether the presence of procaine in crystalloid cardioplegic solution increases myocardial protection at the ultra structural level.
Methods: Eighteen patients that underwent aortic valve replacement in the Hospital de Clínicas de Porto Alegre over a 10-month period were studied. They were randomly allocated into two groups: group A--eight patients receiving cardioplegia without procaine; group B--ten patients receiving cardioplegia with procaine. Myocardial biopsies were performed in three different periods: 1st--before ischemic arrest, 2nd--at the end of ischemic arrest, and 3rd--15 minutes after reperfusion.
Results: The ultra structural analysis comparing the groups in the three moments did not show any statistically significant difference. The mean score in group A at moment I, II and III was 0.1 +/- 0.2; 0.4 +/- 0.3; 0.4 +/- 0.4, and group B 0.2 +/- 0.2; 0.4 +/- 0.3; 0.7 +/- 0.2. Comparative analysis of CK-MB was similar. The spontaneous return to sinus rhythm after aortic declamping in group B occurred in 70% and in group A 12.5% (p=0.024).
Conclusion: Both cardioplegic solutions tested were equally effective in myocardial preservation, and we could not demonstrate at the ultrastructural level any benefit when procaine was added. The spontaneous return to sinus rhythm after aortic declamping was significantly greater when procaine was added.