[Cardioplegia according to Bretschneider for valve replacement: clinical experiences and electronmicroscopical results (author's transl)].

We report about clinical experiences with the cardioplegia according to Bretschneider combined with deep selective hypothermia of the heart in 44 patients. Before, during and after cardioplegia we made biopsies from the left ventricle of 6 patients for electronmicroscopical examinations. Besides the mitochondrial changes already known we saw a break-down of the nexuses. We discuss the importance if these changes for the action of the cardioplegia. Both changes seemed to be reversible. The clinical results and the immediate and later postoperative follow-up demonstrate, that with the described technique a good myocardial protection can be done. This procedure allows operating with a low risk at a completely arrested and relaxed heart until 130 minutes.