1. Therapeutic Drug Monitoring of Class I Antiarrhythmic Agents Without Blood Samples Using High: Resolution Electrocardiography

• Published in: Journal of Nippon Medical School Vol. 70; no. 2; p. 191
• Main Authors: Igor Sutovsky, Takao Katoh, Hideo Takayama, Tadaaki Ohno, Teruo Takano
• Format: Journal Article
• Language: Japanese
• Published: The Medical Association of Nippon Medical School 2003
• ISSN: 1345-4676

Antiarrhythmic therapy requires monitoring of serum drug concentrations to determine a patient's optimal oral dose of medication. Repeated examination of blood samples, however, is costly and time-consuming. We evaluated whether changes in serum concentrations could be estimated from changes in electrocardiographic parameters. Of 36 patients receiving antiarrhythmic drugs for supraventricular or ventricular arrhythmias, 12 were treated with flecainide; 12, pilsicainide; and 12, pirmenol. Signal-averaged electrocardiograms (SAECG) were recorded before starting drug administration, 1 month later, and twice during ongoing therapy. At the time of the second through fourth recordings, we also measured serum concentrations of drugs. As previously reported, all agents prolonged filtered QRS and low amplitude signal duration, especially flecainide and pilsicainide. SAECG parameters varied between recordings during therapy. Differences in filtered QRS duration between two recordings correlated significantly with differences in serum drug concentrations (r=0. 91 for flecainide. r = 0. 70 for pilsicainide, and r = 0. 61 for pirmenol). No significant correlation between drug concentrations and other SAECG parameters was found. Changes in serum concentration of flecainide, pilsicainide and pirmenol can be estimated from changes in filtered QRS duration by SAECG recording. Such periodic monitoring could help to reduce need for repeated measurement of drug concentrations in blood samples.