The use of a wavelet transform for the analysis of nonstationary heart rate variability signal during thrombolytic therapy as a marker of reperfusion

In this study, we used a special wavelet transform algorithm for the analysis of heart rate variability during thrombolytic therapy. The wavelet transform is suitable for time-frequency analysis in non-steady-state conditions and thus provides a time dependent estimation of autonomic activity. Myocardial infarction and reperfusion are known to affect autonomic activity. We examined the dynamics of heart rate fluctuations in concurrence with reperfusion. Clinical reperfusion was determined when a 50% decrease in ST elevations was recorded. We analyzed the heart rate signal obtained from 12 patients, 6 with anterior wall M1 and 6 with inferior wall M1. Mean heart rate and time dependent power spectral estimates of HR fluctuations at 0.1 Hz (LPF) and respiratory rate (HFP) were examined starting 25 min before reperfusion until 25 min after. Our results indicate that in concurrence with reperfusion an increase in the 0.1 Hz peak occurs in anterior wall M1 patients and a reduction of HR occurs in the inferior wall M1 patients