Signal-averaged ECG in prediction of the short-term suppression of ventricular premature beats by Mexiletine.
We analyzed whether baseline parameters of time-domain and spectrotemporal analysis of a signal-averaged ECG or their changes during Mexiletine therapy can predict the antiarrhythmic efficacy of the drug. On 60 post-MI patients with > 100 ventricular premature beats per hour, signal-averaged ECGs were recorded before and after a constant infusion of Mexiletine (7 mg/kg) for 1 h and again after 4 days of oral Mexiletine therapy (Mexiletine SR, 360 mg twice daily). Spectrotemporal analysis was performed on a fixed analyzed signal duration of QRS-complex and ST-segment of X-, Y-, Z-leads using the temporal window of the rectangular type, measuring signals between 10-20 Hz. Intravenous and oral Mexiletine did not produce significant changes in mean values of any time-domain parameters. However, using informative variables of spectra of the signal-averaged ECG, we managed retrospectively to predict antiarrhythmic efficacy in 92% of the patients. Only certain frequency bands (from the range of the spectra at baseline, 10-120 Hz) were predictive for intravenous Mexiletine efficacy: 40-55 Hz in lead Y (P = 0.0116); 55-70 Hz in leads X and Z (P = 0.0063 and P = 0.0269, respectively); 70-85 Hz in lead Z, (P = 0.0227). When the treatment with intravenous Mexiletine was effective, the baseline power spectrum density was lower than when the drug was ineffective, and vice versa. Moreover, the efficacy of oral Mexiletine can be predicted by power density spectrum at baseline (10-25 Hz in lead Z, P = 0.0210; 70-85 Hz in lead Y, P = 0.0254) and by one of the possible (increased, decreased, unchanged) effects of intravenous Mexiletine on the spectra at frequency bands (70-85 Hz in lead X, P = 0.0432 and 40-120 Hz in lead Z, P = 0.0156). These results show the value of spectrotemporal signal-averaged ECG in selecting a subgroup of post-myocardial infarction patients that may benefit from Mexiletine therapy.
Zaliunas
R
R
Department of Cardiology, Kaunas Medical Academy, Lithuania.
Zabiela
P
P
Slapikas
R
R
Vainoras
A
A
Pentiokiniene
D
D
Levisauskiene
R
R
Bechtold
H
H
Meyer
U
U
D000284:Administration, Oral; D000465:Algorithms; D005117:Cardiac Complexes, Premature / Q000209:etiology / Q000517:prevention & control*; D003692:Delayed-Action Preparations; D004562:Electrocardiography / Q000379:methods*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008801:Mexiletine / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications; D011237:Predictive Value of Tests; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors
D003692:Delayed-Action Preparations; D008801:Mexiletine