BACKGROUND AND OBJECTIVE: Arrhythmia is considered as a leading cause of sudden death among patients with cardiac diseases. Since antioxidant agents play a pivotal role in cardiac protection, many of them are used in the form of medicinal plants in traditional medicine. Rosmarinus Officinalis L., commonly known as Rosemary, is a medicinal herb with potent antioxidant properties. This study aimed to evaluate the protective effects of the hydro-alcoholic extract of Rosemary on ventricular arrhythmias in rats.

METHODS: In this experimental study, 32 Sprague-Dawley rats weighing between 250-200 g were divided into two main groups of control and receivers of hydro-alcoholic rosemary extract. The rats received the hydro-alcoholic extract of rosemary (50, 100 and 200 milligrams per kilogram per day via gavage) or Saline (1 ml/kg per day via gavage) for 14 days. Cardiac lead II was recorded in both groups after fourteen days of saline or rosemary extract administration. To induce arrhythmias, CaCl2 (140 kg) solution was injected intravenously, and the incidence of premature ventricular beats (PVB), ventricular tachycardia (VT) and ventricular fibrillation (VF) were also calculated.

FINDINGS: The anti-arrhythmic effects of the hydro-alcoholic extract of rosemary (doses of 100 and 200 mg/kg) were observed following a significant decrease in the occurrence of PVB (75% and 50%, respectively), VT (71.4% and 42.9% %, respectively), and VF (50% and 25%, respectively) compared to the control group. In addition, the highest rate of this reduction occurred in the dosage of 200 mg/kg.

CONCLUSION: According to the results of this study, the hydro-alcoholic extract of rosemary could be used as a protective substance providing cardiac pre-conditioning against ventricular arrhythmias