Antonio Dello Russo, Lucia De Luca, Cesare Santini*, Loredana Messano, Giuseppe De Martino, Vincenzo Giglio*, Fortunato Mangiola*, Enzo Ricci*, Antonello Damiani*, Gaetano Antonio Lanza, Fulvio Bellocci.
Cardiology Division, Department of Medicine, State University of New York, Health Science Center and Veterans Affairs Medical Center, Brooklyn, USA Istituto di Cardiologia, Universita Cattolica,
*Centro per le Malattie Neuromuscolari, Unione Italiana Lotta alla Distrofia Muscolare, Rome, Italy
|
|
BACKGROUND. Cardiac involvement and autonomic dysfunction are
frequent in patients with Duchenne muscular dystrophy. Aim of this study was to characterize cardiac autonomic
function in these patients and to investigate the relationship with myocardial left ventricular function.
METHODS. Time and frequency-domain heart rate variability analysis was performed on 24-hour Holter
electrocardiographic recording of 60 Duchenne muscular dystrophy patients (16.8±4.8 years) and of 28 healthy
controls (15.2±4.6 years). Circadian rhythm of hourly RR interval, low-frequency (LF), high-frequency (HF), and
LF/HF ratio was also assessed. Left ventricular size and function was evaluated by two-dimensional
echocardiography.
RESULTS. All time and frequency domain heart rate variability parameters were significantly lower in Duchenne
muscular dystrophy patients than in controls, with pNN50 (11.6±8.5% vs 27.3±14.1%, p= 0.00001) and HF (23.9±10.3
vs 36.1±12.2 msec, p =0.0001) showing the strongest differences. A significant circadian rhythm of heart rate
variability variables was present in both groups, but it was considerably flattened in Duchenne muscular
dystrophy patients. Left ventricular ejection fraction was significantly reduced in Duchenne muscular dystrophy
patients, compared to controls (46.2±10.2% vs 58.1±5.2%, p=0.00001), but there was no significant correlation
between heart rate variability indexes and myocardial function, except for a weak correlation with HF (r=0.30;
p =0.02) and with LF/HF ratio (r=-0.29; p<0.03). The analysis in subgroups of Duchenne muscular dystrophy
patients with age of <15, 15-20, and >20 years revealed that heart rate variability was already significantly
impaired in the youngest group, who still had preserved left ventricular function.
CONCLUSION. Our data show a marked impairment of cardiac autonomic function in Duchenne muscular
dystrophy patients, which seems largely independent of left ventricular systolic function.
|
