A comparative study on enzymatic data from myocardial biopsies and cardiac function in patients who underwent cardiac...

Twenty-three patients underwent cardiac surgery for valve replacement, valve reconstruction, aorto-coronary bypass grafting, aneurysmectomy or combinations of these. Excised cardiac tissue was obtained from left ventricular (LV) papillary muscle (17 patients), LV outflow tract (3 patients), or LV aneurysms (3 patients). A total of 34 myocardial samples, collected from excised cardiac tissue, were analysed for creatine kinase (CK), CK-isoenzymes, cytoplasmic and mitochondrial isoenzymes of aspartate aminotransferase (cAST and mAST, respectively), and lactate dehydrogenase (LDH) isoenzymes. Myocardial CK activity correlated positively with preoperative LV ejection fraction (p less than 0.001), negatively with the preoperatively measured extent of LV wall motion abnormalities (p less than 0.001), and negatively with preoperative LVEDP (p less than 0.02). Myocardial CK activity was negatively correlated with preoperative validity class (p less than 0.005). However, no correlation existed between myocardial CK activity and postoperative validity. Excluding the biopsies from LV aneurysms, myocardial CK activity was positively correlated with the fraction H-subunits in LDH (p = 0.02), and was negatively correlated with the fraction mAST in total AST (p less than 0.005). While cAST activity was proportional to CK activity in the biopsies from VL papillary muscle and LV outflow tract, mAST activity declined only with 2.4 +/- 1.2% per 10% fall of CK. The increase of mAST/cAST ratio with decreasing CK, together with the decrease of LDH-H/LDH and CK-M/CK ratios with decreasing CK, indicated the presence of an adaptation process in a myocardium with low CK activity rather than a process of necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)