Metabolic alterations in end-stage and less severe heart failure--myocardial carnitine decrease

Severe tissue carnitine deficiency impairs fatty acid oxidation. In explanted hearts from patients with end stage heart failure a 57% carnitine decrease was found in comparison with healthy donor hearts (p less than 0.05). The reduction of myocardial carnitine levels affected all areas of the explanted hearts to a comparable extent. Carnitine decreases in patients with dilated cardiomyopathy or coronary artery disease were similar. Endomyocardial biopsies from patients with less severe heart failure due to cardiomyopathy (n = 28) or other myocardial diseases (n = 8) showed a 42% decrease of total myocardial carnitine (in nmol/mg non-collagen protein) in comparison with biopsies from patients with normal cardiac function (controls) (heart failure: 5.7, confidence interval 4.2-7.0; controls 9.3, confidence interval 7.6-12.0, p less than 0.005). Free myocardial carnitine in heart failure was also different from controls (heart failure: 4.2, confidence interval 3.7-5.3; controls 10.3, confidence interval 7.5-12.2, p less than 0.001). The decrease of free and total myocardial carnitine was comparable in dilated cardiomyopathy and heart failure due to other diseases. Alterations in myocardial carnitine content represent therefore non-specific biochemical markers in heart failure with yet unknown consequences for myocardial function.