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Electrophysiological actions of lorcainide in patients with cardiac disease
Abstract:
Lorcainide is a new antiarrhythmic agent which effectively suppresses ventricular premature contractions. Its electrophysiological actions were studied in 15 cardiac patients with and without cardiac conduction abnormalities. In a dose of 2 mg/kg body weight, lorcainide decreased the sinus cycle length (SCL) and increased the corrected sinus node recovery time. The intra-atrial, atrioventricular (AV), and intraventricular conduction times were prolonged. A third-degree AV block developed in 2 patients with pre-existing conduction abnormalities. QRS widening showed that intramyocardial conduction was also affected. The effective refractory period of the atrioventricular node (ERP-AVN) was shortened, whereas the effect on the functional refractory period of the AVN was variable. The decrease in SCL and ERP-AVN may be due to a possible anticholinergic effect of the drug. The accessory pathway was blocked in 3 patients with a Wolff-Parkinson-White syndrome. The ERP of the ventricle was slightly prolonged. The electrophysiological profile of the drug, i.e., slowing of conduction velocity throughout the heart combined with shortening of SCL and ERP-AVN, differs from other antiarrhythmic agents.
Insights
Lorcainide effectively suppresses ventricular arrhythmias by altering cardiac electrophysiology. This antiarrhythmic agent slows conduction, shortens the sinus cycle length, and affects refractory periods, differing from other treatments.
Area of Science:
- Cardiology
- Pharmacology
- Electrophysiology
Background:
- Lorcainide is a novel antiarrhythmic drug.
- Ventricular premature contractions (VPCs) are a target for antiarrhythmic therapy.
Purpose of the Study:
- To investigate the electrophysiological actions of lorainide.
- To assess lorainide's effects in patients with and without cardiac conduction abnormalities.
Main Methods:
- Electrophysiological studies were conducted in 15 cardiac patients.
- Lorcainide was administered at a dose of 2 mg/kg body weight.
Main Results:
- Lorcainide decreased sinus cycle length (SCL) and increased corrected sinus node recovery time.
- Conduction times (intra-atrial, atrioventricular, intraventricular) were prolonged, with QRS widening observed.
- Effective refractory period of the atrioventricular node (ERP-AVN) was shortened, while effects on functional refractory period were variable. Accessory pathways were blocked in Wolff-Parkinson-White syndrome patients.
Conclusions:
- Lorcainide exhibits a unique electrophysiological profile, slowing cardiac conduction and affecting refractory periods.
- The drug's effects may involve anticholinergic properties.
- Lorcainide demonstrates efficacy in suppressing ventricular arrhythmias and blocking accessory pathways.