¹H- and ³¹P-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 ³¹P-MRS and ¹H-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 ¹H-MRS and multivoxel ³¹P-MRS. ¹H-MRS was performed after imaging using standard coil with the patient in the supine position; thereafter, ³¹P-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/m², septal thickness 10 (10–11) mm, end diastolic volume index 95 (85–102) ml/m², end systolic volume index 30 (28–32) ml/m² and ejection fraction 68% (65–69%); in HCM patients, 81 (76–111) g/m² (P = 0.052), 18 (15–21) mm (P = 0.003), 73 (58–76) ml/m² (P = 0.029), 20 (16–34) ml/m² (P = 0.274) and 68% (55–73%) (P = 1.000), respectively. At ¹H-MRS, total lipids were 35 (0–183) arbitrary units (au) for CA and 763 (155–1994) au for HCM patients (P = 0.046). At ³¹P-MRS, PCr/γATP 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 ¹H-MRS and 15 min for ³¹P-MRS. Conclusions: We observed a significant increase of myocardial lipids, but a preserved PCr/γATP ratio in the metabolism of HCM patients compared with competitive CAs.