Impaired cardiac energetics in dilated cardiomyopathy - magnetic resonance spectroscopy at 3T

IntroductionThe aim was to measure the cardiac phosphocreatine to ATP (PCr/ATP) ratio non-invasively in patients with dilated cardiomyopathy and normal controls, and to correlate the patient9s results to symptom status, ejection fraction (EF) and quality of life scores. Dilated cardiomyopathy is known to be associated with cardiac energy deficiency. Magnetic resonance spectroscopy (MRS) has been proposed as a non-invasive method of assessing cardiac energetics and as a method of measuring response to therapy. Interrogation at high field strength improves signal to noise ratio.Methods32 patients and 22 control subjects were studied using phosphorus-31 (31P) MRS and patients were classified to NYHA symptom class. In vivo energetics were measured using a commercially available Philips Achieva 3 Tesla scanner and dedicated 31P coil with ISIS volume selection. Java Magnetic Resonance User Interface (jMRUI) was used for analysis. Furthermore, all patients completed a Minnesota Living with Heart Failure (MLWHF) score and underwent echocardiography. LVEF was measured using biplane Simpson9s method.ResultsThe PCr/ATP ratio was significantly reduced in patients (1.35±0.31) compared with control subjects (1.90±0.40; p<0.005). The PCr/ATP ratio was correlated with NHYA class (r=−0.68, n=32, p<0.0005). No correlation was found with LVEF or MLWHF score.ConclusionsThis study confirms the presence of energy deficiency in dilated cardiomyopathy as measured by MRS at 3T. The energy status correlates strongly with symptom status but not with ejection fraction nor quality of life score. Cardiac energetic status is directly proportional to symptoms status and therefore any treatments targeted to improve cardiac energetics may improve patient symptoms in dilated cardiomyopathy.