The Relationship between Plasma BNP Level and the Myocardial Phosphocreatine/Adenosine Triphosphate Ratio Determined by Phosphorus-31 Magnetic Resonance Spectroscopy in Patients with Dilated Cardiomyopathy

The purpose of this study was to evaluate the correlation between the plasma B-type natriuretic peptide (BNP) level and the myocardial phosphocreatine/adenosine triphosphate ratio determined using rapid phosphorus-31 magnetic resonance spectroscopy (31P-MRS) in patients with dilated cardiomyopathy (DCM). Thirteen DCM patients, who had slight or moderate heart failure, were examined. The plasma BNP was measured on a day close to the rapid 31P-MRS study. 31P-MRS measurements were conducted with a 1.5-T MR instrument. The plasma BNP levels tended to be correlated negatively with the myocardial phosphocreatine/adenosine triphosphate, although the correlation did not reach statistical significance (r = -0.54, p = 0.06). By contrast, the log of the plasma BNP levels was correlated negatively with the myocardial phosphocreatine/adenosine triphosphate (r = -0.73, p < 0.01). Our results indicate that the myocardial energy metabolism evaluated using 31P-MRS tends to be correlated with the severity of heart failure and left ventricular dysfunction estimated using the plasma BNP levels in DCM patients. This paper provides additional information regarding the relationship between the BNP and myocardial energy metabolism in DCM patients.