[Carnitine metabolism--changes in the end stage of dilated cardiomyopathy and ischemic heart muscle disease].

Biochemical analyses from endomyocardial biopsies indicate that cardiac energy metabolism is altered in patients with end-stage cardiac failure. Myocardial energy production is predominantly based on fatty acid oxidation. Carnitine, a naturally occurring compound, plays an essential role in fatty acid oxidation by carrying long-chain fatty acids into the mitochondrial matrix where they undergo beta-oxidation. In experimental animals, myocardial carnitine deficiency may cause cardiomyopathies which are reversible with carnitine substitution. Rare human diseases, as systemic carnitine deficiency, are associated with impaired cardiac function. We therefore investigated carnitine metabolism in patients with cardiac failure. Plasma and myocardial carnitine levels were measured in 55 patients undergoing cardiac transplantation because of end-stage cardiac failure based on dilated cardiomyopathy (DC, n = 30) or coronary artery disease (CAD, n = 22). Elevated plasma carnitine levels (controls: 49 +/- 12 microM; DC: 82 +/- 38 microM; p less than 0.001, CAD: 86.9 +/- 21.6 microM; p less than 0.05) were found in both patient groups (Fig. 1). Plasma carnitine did not correlate with creatinine (Fig. 2). Compared to controls, myocardial carnitine levels were significantly reduced: DC: 5.9 +/- 1.45 nmol/mg NCP; CAD: 5.84 +/- 1.84 nmol/mg NCP; controls: 15.6 +/- 5.4 nmol/mg NCP (Fig. 3). No correlation between myocardial and plasma levels was found (Fig. 5).(ABSTRACT TRUNCATED AT 250 WORDS)