Usefulness of Wavelet-Transformed Electrocardiogram for Detection of Ventricular Tachyarrhythmias Associated with Hypertrophic Obstructive Cardiomyopathy

Abstract

Background: Wavelet-transform is a novel time-frequency analysis on surface electrocardiogram (ECG) in detection of high-frequency components (HFCs) intra-QRS complex, suggesting abnormal myocardial conductions. We evaluated usefulness of Wavelet-transformed ECG in detection of ventricular tachyarrhythmia (VTA) in hypertrophic obstructive cardiomyopathy (HOCM). Methods: We studied 30 patients, including VTA group (N=7) and Non-VTA group (N=23). 12-lead ECG (sampling=10 kHz) was recorded and the representative QRS complex (300 ms) was transformed using Gabor function to the power curve along a time course. Percentages of peak power values at each frequency (120, 150, and 200 Hz) in the corresponding power values at 40 Hz (P120/40, P150/40, and P200/40, respectively) were calculated. “The percentage ≥50%” was defined as an abnormal-HFC and the number of leads in which an abnormal-HFC was detected of 12 leads (NL-AHFC) was counted. Results: P120/40, P150/40, and P200/40 in VTA group were significantly higher than those in Non-VTA group (45.0±25.2 vs 27.2±7.5, P<0.05; 41.4±23.2 vs 25.2±7.4, P=0.05; 45.1±20.9 vs 22.3±8.2, P=0.05, respectively). NL-AHFC (P120/40) in VTA group increased more than those in Non-VTA group (4.1±1.2 vs 1.1±2.1, P<0.05). When “NL-AHFC (P120/40) ≥3” was defined as abnormal, the sensitivity, specificity, positive and negative predictive values for detection of VTA were 86, 92, 75, 96%, respectively. Conclusion: Wavelet-transform might be a novel method to detect arrhythmogenic substrates in HOCM.