Abnormal signal‐averaged electrocardiogram in patients with duchenne muscular dystrophy: Comparison of time and frequency domain analyses from the signal‐averaged electrocardiogram

Abstract

Summary:The clinical significance of an abnormal signal-averased electrocardiogram (SA-ECG) in time-and frequencydomain analyses was assessed in patients with Duchenne muscular dystrophy (DMD). Twenty-four DMD patients and 20 age-matched healthy volunteers were studied. The SA-ECG was recorded by timedomain signal processing using the vector-magnitude method and frequency-domain signal processing using the fast-Fourier transform. Abnormal SA-ECGs were based on comparison with controls and eight abnormal SAECGs were detected among 24 DMD patients, seven by frequency-domain analysis and four by timedomain analysis. The end-diastolic left ventricular volume was larger in the patients with abnormal SA-ECG than in those with normal SA-ECG (136+_32mlvs.77+_43 rnl,p<O.Ol).Comparedwithpatients with normal SA-ECGs, the DMD patients with abnormal SAECGs had a lower left ventricular (LV) ejection fraction (54 f 6 vs. 61 It 8%, p < 0.05), as an index of LV contractility, and less LV posterior wall velocity (46 k 9 rnm/rnin vs. 62 k 16 mml min, p 4 . 0 I ), as an index of LV relaxation. The sensitivity and specificity of frequency-domain analysis for predicting malignant ventricular arrhythmias was 60 and 85%, respectively, compared with 30 and 92%. respectively, for timedomain analysis. The combination of time-and frequency-domain analyses can facilitate identification of DMD patients with ventric- ular tachyarrhythmias associated with depression of cardiac performance.

Evaluation of Dysrhythmia in Children with Muscular Dystrophy

“…The study group consisted of 29 children with muscular dystrophy (14 Duchenne muscular dystrophy, seven Becker muscular dystrophy, and eight female carriers) aged 1.5-17 years (mean, 8.1 ±4.34 years) and 29 healthy control subjects aged 3-14 years (mean, 8.3 ±3.01 years). All patients underwent M-mode and pulsed wave Doppler echocardiography and multigated radionuclide ventriculography for systolic and diastolic functions.…”