Effect of flecainide on regional left ventricular wall motion after acute intravenous, acute oral and chronic oral administration late after coronary artery bypass grafting

Abstract

Epicardial marker motion was measured in 14 patients before flecainide administration, immediately after an intravenous dose of 2 mg/kg over 15 minutes (maximum' 150 mg) and 15 minutes thereafter. Platinum epicardial markers had been implanted more than 4 years earlier at the time of coronary artery bypass grafting. Maximal and minimal marker separation (Lmax and Lmin) during the cardiac cycle were measured and regional shortening fraction (Lmax -Lmin)/Lmax) was determined as a per: centage. After intravenous flecainide, a significant increase in end-diastolic (immediately after 2.8%; after 15 minutes 2.1% ) and end-systolic (3.8 % and 3.2% ) regional dimensions was observed, together with a decrease in regional myocardial shortening (9.3% and 9.0%). One week later, after a single oral dose of 200 mg of flecainide, Lmax and Lmin had increased 2.4 % and 2.7 % , while regional myocardial shortening did not differ significantly, from baseline values. In 19 patients measurements were repeated after 8 weeks of chronic oral treatment with 300 mg/day. Despite plasma flecainide levels similar to those after intravenous administration, no significant changes.in'end-diastolic and end-systolic dimensions or regional shortening fraction were observed. Thus, acute intravenous or oral flecainide administration increases regional end-diastolic and end-systolic dimensions, but only intravenous administration decreases regional shortening fraction. Values during chronic administration indicate that regional myocardial function is more affected at the time of rising or acutely changing flecainide plasma levels than when stable plasma levels are achieved.( Am J Cardiol 1988;58:470-475) F lecainide acetate, an antiarrhythmic agent that slows atrial, nodal and ventricular conduction and increases atria1 and ventricular refractoriness,1-4 is effective in suppressing ventricular arrhythmias and reentrant tachycardias related to anomalous atrioventricular pathways4-l2A myocardial depressant effect after intravenous administration of flecainide in humans has been reported,13-l5 whereas echocardiographic measures of From the Thoraxcenter, University Hospital "Dijkzigt," Rotterdam, The Netherlands. Manuscript

Intracoronary Flecainide Induces ST Alternans and Reentrant Arrhythmia on Intact Canine Heart

“…Sixty epicardial electrograms were simultaneously recorded at control, 10 minutes after the low dose, 10 minutes after the high-dose infusion, and just before ventricular fibrillation (VF), if VF occurred. In addition, the therapeutic dose of flecainide (0.2 mg/kg over 15 minutes) 17 was investigated with the intravenous infusion because high-dose flecainide induces ST a and VF.…”