Changes in the heart rate of rats treated with verapamil overdose and resuscitated with lipid emulsion

Abstract

Introduction: Verapamil is a drug that is used often due to its wide spectrum of action. Many authors consider it to be the most dangerous of the calcium channel blockers due to its negative chronotropic and inotropic effect on the heart, leading to severe cardiodepression. Overdose is difficult to treat and is associated with high mortality despite existing treatment options. Over the last 15 years, lipid emulsions (LEs) have been increasingly used for resuscitation after overdosing with lipophilic drugs such as verapamil. Despite the convincing results and the improved patient status, the association of the administration of LE with the recovery of patients may be questioned since LE was given in addition to standard therapy. Aim: The aim of this article is to conduct an evaluation of the self-cardioprotective effect of LE in acute verapamil overdose (15 mg/kg) in rats by measurement of the heart rate and survival at the recommended LE dose of 1.5 mL/kg and 7 times the recommended LE dose (10 mL/kg). Material and Methods: The experiment was performed on 30 male Wistar rats, provided by the Medical University of Varna. Instrumental methods included monitoring the heart rate of rats using an electrocardiographic monitor. The statistical analysis was performed using the statistical functions in Excel 2016 and Statistica 7.0. Results: A survival rate of 100% was observed in rats pretreated and treated with low and high LE dose. The high LE dose (10 mL/kg) showed a faster improvement in cardiac function as the highest mean heart rates were established. Conclusion: Pretreatment and resuscitation with low or high LE dose reduce toxicity and prevent dose-dependent asystole induced by verapamil. The administration of a high LE dose (10 mL/kg) proved to be more effective in terms of heart rate in rats.