H-1- and P-31-myocardial magnetic resonance spectroscopy in non-obstructive hypertrophic cardiomyopathy patients and competitive athletes

Purpose The clinical differentiation between athlete's heart and mild forms of non-obstructive hypertrophic cardiomyopathy (HCM) is crucial. We hypothesized that differences do exist between the myocardial metabolism of patients with non-obstructive HCM and competitive athletes (CAs). Our aim was to evaluate myocardial metabolism with P-31-MRS and H-1-MRS in HCM patients and CAs. Materials and methods After Ethics Committee approval, 15 CAs and 7 HCM patients were prospectively enrolled. They underwent a 1.5-T cardiac MR including electrocardiographically triggered cine images, single-voxel H-1-MRS and multivoxel P-31-MRS. H-1-MRS was performed after imaging using standard coil with the patient in the supine position; thereafter, P-31-MRS was performed using a dedicated coil, in the prone position. Data were reported as median and interquartile range. Mann-Whitney U test was used. Results In CAs, left ventricular mass index was 72 (66-83) g/m(2), septal thickness 10 (10-11) mm, end diastolic volume index 95 (85-102) ml/m(2), end systolic volume index 30 (28-32) ml/m(2) and ejection fraction 68% (65-69%); in HCM patients, 81 (76-111) g/m(2) (P = 0.052), 18 (15-21) mm (P = 0.003), 73 (58-76) ml/m(2) (P = 0.029), 20 (16-34) ml/m(2) (P = 0.274) and 68% (55-73%) (P = 1.000), respectively. At H-1-MRS, total lipids were 35 (0-183) arbitrary units (au) for CA and 763 (155-1994) au for HCM patients (P = 0.046). At P-31-MRS, PCr/gamma ATP was 5 (4-6) au for CA and 4 (2-5) au for HCM patients (P = 0.230). Examination time was 20 min for imaging only, 5 min for H-1-MRS and 15 min for P-31-MRS. Conclusions We observed a significant increase of myocardial lipids, but a preserved PCr/gamma ATP ratio in the metabolism of HCM patients compared with competitive CAs.