[The effects of long-term treatment of sotalol hydrochloride on time and frequency domain parameters of signal averaged electrocardiogram in patients with ischemic heart disease]

Abstract

The aim of this study was to assess the influence of sotalol hydrochloride on time- and frequency-domain parameters of signal-averaged electrocardiogram (SAECG) in patients with ischemic heart disease (IHD). The study population consisted of 25 patients (16 women and 9 men), mean age 56.6 +/- 8.3. Sotalol was orally used in dose 160 mg/day during 6 weeks. Recording of SAECG and ambulatory Holter monitoring were made at baseline and in 10 day and after 6 weeks of therapy. The following time-domain parameters were analyzed: the root mean square voltage of the last 40 and 50ms of the filtered QRS (RMS 40 i RMS 50), total time duration of filtered QRS (t-QRS) and duration of low amplitude signals < 40 microV in the terminal part of QRS (LPD). Late potentials (LP) were recognized when at least two from three criteria were fulfilled: 1) RMS40 < 20 microV, 2) t-QRS > 114 ms, 3) LPD > 38ms. Frequency analysis of SAECG allowed to calculate the following parameters in logarithmic scale: energy spectrum > -60dB (A) and decibel drop at 40 Hz (Dd) and also in linear scale: area ratio 20-50/0-20 Hz (Ar) and magnitude ratio (MR1-7). The values of RMS40 and RMS50 and also t-QRS and LPD did not significantly change after sotalol treatment. At baseline the presence of LP was recorded in 7 (28%) cases, after 10 days of antiarrhythmic therapy only in 3 (12%), and after 6 weeks occurred in 6 (24%) cases. Moreover, sotalol hydrochloride did not statistically significant change frequency-domain parameters in logarithmic scale: A and Dd. On the other hand, the parameters in linear scale: MR1, MR4 and MR6 significantly change but these changes were not uniform. These findings suggest that oral treatment of sotalol hydrochloride did not significantly change time- and frequency-domain parameters of signal-averaged electrocardiogram in patients with ischemic heart disease.