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The Effects of Intravenous Mexiletine on Spectra of the Signal‐Averaged ECG
Author(s) -
ZALIUNAS REMIGIJUS,
ZABIELA PETRAS,
SLAPIKAS RIMVYDAS,
VAINORAS ALFONSAS,
PENTIOKINIENE DAIVA,
LEVISAUSKIENE REGINA,
BECHTOLD HEINRICH,
MEYER ULRIKE
Publication year - 1994
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1994.tb03824.x
Subject(s) - mexiletine , medicine , signal averaged electrocardiogram , qrs complex , cardiology , lead (geology) , myocardial infarction , electrocardiography , anesthesia , geomorphology , geology
This study examined the effects of intravenous mexiletine on the time‐domain and spectrotemporal signal‐averaged ECG (SAECG). SAECGs were recorded in 60 postmyocardial infarction (MI) patients with more than 100 premature ventricular beats per hour, before and after a constant infusion of mexiletine, 7 mg/ kg, given over 1 hour. Spectrotemporal analysis was done on a fixed analyzed signal duration of QRS complex and ST segment of X, Y, and Z leads using a temporal window of rectangular type, measuring the signal content between 10–120 Hz. Intravenous mexiletine produced no significant change in the mean values of any of the time‐domain variables. However, mexiletine either increased or decreased the power density spectrum (PDS) and PDS ratio (40–120 Hz/25–120 Hz) of the SAECG. and in rare cases only did it not alter the spectra of the SAECG. When PDS ratio in lead Z decreased after mexiletine, it was usually higher at baseline in comparison with that when the PDS ratio increased, or vice versa. When the treatment with mexiletine was effective, PDS increased in comparison with that when the drug was ineffective, or vice versa. Not all ranges (10–120 Hz) of spectra of the SAECG, but only certain frequency bands (25–40 Hz in lead Z,P = 0.0253; 40–55 Hz in lead Y, P = 0.0096; 55–70 Hz in Xlead, P = 0.0018; and in lead Z, P = 0.0002; 70–85 Hz in lead X, P = 0.0025; and in lead Z, P = 0.0075, 85–100 Hz in lead X, P = 0.0033) were associated with mexiletine efficacy. However, PDS ratio changes after mexiletine did not correlate with drug efficacy as measured by Holter monitoring. These results might provide a new understanding relative to the role and impact of mexiletine therapy in post‐MI patients.