Cerebral metabolic abnormalities in congestive heart failure detected by proton magnetic resonance spectroscopy

OBJECTIVES: Using proton magnetic resonance spectroscopy, we investigated cerebral metabolism and its determinants in congestive heart failure (CHF), and the effects of cardiac transplantation on these measurements. BACKGROUND: Few data are available about cerebral metabolism in CHF. METHODS: Fifty patients with CHF (ejection fraction ≤35%) and 20 healthy volunteers were included for this study. Of the patients, 10 patients underwent heart transplantation. All subjects performed symptom-limited bicycle exercise test. Proton magnetic resonance spectroscopy (¹H MRS) was obtained from localized regions (8 to 10 ml) of occipital gray matter (OGM) and parietal white matter (PWM). Absolute levels of the metabolites (N- acetylaspartate, creatine, choline, myo-inositol) were calculated. RESULTS: In PWM only creatine level was significantly lower in CHF than in control subjects, but in OGM all four metabolite levels were decreased in CHF. The creatine level was independently correlated with half-recovery time and duration of heart failure symptoms in PWM (r = -0.56, p < 0.05), and with peak oxygen consumption and serum sodium concentration in OGM (r = 0.58, p < 0.05). Cerebral metabolic abnormalities were improved after successful cardiac transplantation. CONCLUSIONS: This study shows that cerebral metabolism is abnormally deranged in advanced CHF and it may serve as a potential marker of the disease severity.