Plasma carnitine levels as a marker of impaired left ventricular functions.

L-Carnitine plays a role in the utilization of fatty acids and glucose in the myocardium. Previous studies have indicated carnitine deficiency in patients with congestive heart failure. However, the extent of altered carnitine metabolism and left ventricular function is not fully determined. This study is designed to determine if plasma L-carnitine levels can serve as a marker for impaired left ventricular function in patients with congestive heart failure. To test this hypothesis, plasma and urinary levels of L-carnitine were measured in 30 patients with congestive heart failure (CHF) and in 10 control subjects. CHF was due to dilated cardiomyopathy (DCM) and rheumatic heart disease (RHD). Cardiac functions such as percentage of fractional shortening (%FS), ejection fraction (EF), left ventricular mass index (LVMI), were determined by echocardiography. All patients and control subjects had normal renal functions. Plasma carnitine was significantly higher in patients with DCM (37.05+/-7.62, p < 0.0001) and with RHD (47.2+/-8.04, p < 0.0001) vs. the control subjects (14.4+/-5.30 mg/L). Urinary carnitine was significantly higher in DCM (49.13+/-14.11, p < 0.0001) and in RHD 43.53+/-15.5, p < 0.0001), than the control (25.1+/-5.78 mg/L). Plasma carnitine level correlated significantly with impaired left ventricular systolic functions in these patients: % FS < 25 % (r = -0.38 and p = 0.038), EF < 0.55 (r = -0.502 and p = 0.005) and LMVI > 124 gm/m2 (r = 0.436, and p = 0.016). These data suggest that elevated plasma and urinary carnitine levels in patients with CHF could serve as a marker for myocardial damage and impaired left ventricular functions.