Impaired left ventricular energy metabolism in patients with hypertrophic cardiomyopathy is related to the extension of fibrosis at delayed gadolinium-enhanced magnetic resonance imaging.
OBJECTIVE
Areas of intramyocardial late enhancement (LE) at delayed enhanced magnetic resonance imaging (DE-MRI) and reduction of myocardial phosphocreatine (PCr)/ATP-ratio at phosphorus magnetic resonance spectroscopy ((31)P-MRS) are both reported in hypertrophic cardiomyopathy (HCM) and indicate areas of increased interstitial myocardial space with fibrosis and impairment of myocardial energy metabolism, respectively. We sought to ascertain whether in HCM patients the abnormal features of left ventricular (LV) interstitial space revealed by DE-MRI correlated with impaired LV energy metabolism shown at (31)P-MRS.


METHODS
19 patients with HCM proved by histological analysis of multiple endomyocardial biopsies and with normal coronary arteries, underwent cardiac MRI including DE-MRI and (31)P-MRS. DE-MRI for detection and quantification of late enhancement (LE) and (31)P-MRS to assess the myocardial PCr/ATP-ratio were performed by means of a 1.5-T magnet. 19 healthy subjects, matched for gender and age were studied by (31)P-MRS as control group.


RESULTS
LE areas in the LV wall were found in 17 out of 19 patients with an extension ranging from 0.8% to 19.5% of the LV-mass (mean value 7.6% (SD 5.6%). The PCr/ATP-ratio was lower in HCM patients than in control subjects (2.18 (0.41) vs 2.41 (0.30); p<0.05). LE% and PCr/ATP-ratio were inversely related (R = -0.57; p<0.05) and LE% was the stronger predictor of PCr/ATP-ratio by multivariate analysis.


CONCLUSIONS
This study demonstrated that the known alteration of the PCr/ATP-ratio observed in HCM patients is correlated with the presence of fibrotic areas in the myocardium of the left ventricle.
Esposito
A
A
Department of Radiology, San Raffaele Scientific Institute, Vita Salute San Raffaele University, Via Olgettina 60, 20132, Milan, Italy. esposito.antonio@hsr.it
De Cobelli
F
F
Perseghin
G
G
Pieroni
M
M
Belloni
E
E
Mellone
R
R
Canu
T
T
Gentinetta
F
F
Scifo
P
P
Chimenti
C
C
Frustaci
A
A
Luzi
L
L
Maseri
A
A
Maschio
A Del
AD
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000378:metabolism*; D016022:Case-Control Studies; D003287:Contrast Media; D042241:Early Diagnosis; D004719:Endomyocardial Fibrosis / Q000378:metabolism* / Q000473:pathology; D004734:Energy Metabolism; D005260:Female; D005355:Fibrosis; D005682:Gadolinium; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D010725:Phosphocreatine / Q000378:metabolism*; D013318:Stroke Volume
D003287:Contrast Media; D010725:Phosphocreatine; D000255:Adenosine Triphosphate; D005682:Gadolinium