Time-frequency analysis of QRS complex with wavelet transform in patients with triple-vessel disease

Objective: Significant Q-wave is sometimes invisible in the patients with triple vessel disease (TVD) even though TVD is a serious coronary heart disease. We offer the preliminary method to analyze the time-frequency profile of QRS in TVD patients. Methods: Electrocardiograms (ECG) band-pass filtered through 50 to 300Hz were recorded from the persons without heart diseases (Normal group; n=24), the patients with single vessel disease (SVD group; n=12) and TVD (TVD group; n=12) and saved into PC. For each subject, the time-frequency powers of ECG (lead II) were calculated by the continuous wavelet transform (CWT) with 40 frequency bands. They were integrated during QRS to get the integrated time-frequency powers (ITFP) for all the frequency bands. Results: The ITFP at lower frequency range (90Hz or less) were smaller in SVD and TVD groups, compared with normal group. The ITFP at higher frequency range (120 to 350Hz) were larger in patients with recurrent heart failure due to TVD. The increase in ITFP at wider frequency bands was seen with and without significant Q-waves. Conclusion: The present results that the increase in higher frequency power in TVD with recurrent heart failure may indicate the severity of myocardial damage, regardless of significant Q-wave.