Bepridil Inhibits Premature Ventricular Complexes Induced by Cardio-Sympathetic Nerve Stimulation in a Canine...

Area of Science:

• Cardiology
• Pharmacology
• Autonomic Nervous System Research

Background:

• Enhanced sympathetic nerve activity can trigger ventricular arrhythmias, particularly in patients with heart disease.
• Beta-blockers are standard treatment, but some patients cannot tolerate sufficient doses.
• Bepridil, a novel ionic current inhibitor, lacks beta-adrenergic effects and was investigated for anti-arrhythmic potential.

Purpose of the Study:

• To evaluate the anti-arrhythmic effects of bepridil on premature ventricular beats induced by stellate ganglion stimulation in a canine model.
• To assess the pro-arrhythmic potential of bepridil under conditions of enhanced sympathetic drive and autonomic testing.
• To determine bepridil's impact on heart rate variability and autonomic responses during sympathetic stimulation.

Main Methods:

• Canine model with stellate ganglion (SG) stimulation to augment cardio-sympathetic nerve activity.
• Administration of bepridil at 2 mg/kg and 4 mg/kg intravenously to assess dose-dependent effects.
• Evaluation of premature beat induction, frequency, and pro-arrhythmic potential using programmed electrical stimulation and vagal stimulation.
• Analysis of heart rate variability (HRV) indexes to monitor cardio-autonomic function.

Main Results:

• Stellate ganglion stimulation increased blood pressure and heart rate, inducing premature beats in 10/16 instances, predominantly with left SG stimulation.
• Bepridil at 2 mg/kg reduced premature beat burden but did not eliminate inducibility; 4 mg/kg administration resulted in only one instance of inducible premature beats.
• No pro-arrhythmic effects were observed, and bepridil did not significantly alter steady-state HRV indexes or SG-stimulation-induced hemodynamic responses.

Conclusions:

• Bepridil demonstrated significant anti-arrhythmic efficacy against sympathetically mediated premature ventricular beats in this canine model.
• The drug appears safe, with no observed pro-arrhythmic effects and minimal impact on overall autonomic nerve activity.
• Bepridil represents a potential therapeutic option for managing ventricular arrhythmias associated with heightened sympathetic tone, especially when beta-blockers are contraindicated or insufficient.