Basic nutritional investigation Effects of garlic on the induction of ventricular fibrillation Rattapong Sungnoon, M.D., Natnicha Kanlop, M.D., Siriporn C. Chattipakorn, Ph.D., Rodjana Tawan, AAS, and Nipon Chattipakorn, M.D., Ph.D.* Cardiac Electrophysiology Unit, Department of Physiology, and Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Manuscript received September 13, 2007; accepted March 5, 2008. Abstract Objective: Previous studies have shown that oral and intravenous administrations of garlic provide a significant antiarrhythmic effect and improve defibrillation efficacy. We tested the hypothesis that garlic could decrease the inducibility of ventricular arrhythmia. Methods: Twenty-one pigs (25–30 kg) were divided into three groups. In each group, the ventricular fibrillation threshold (VFT) and the upper limit of vulnerability (ULV) were determined. After the control VFT and ULV values were obtained, solutions containing 20 mg/kg (group 1, n = 7) and 40 mg/kg (group 2, n = 7) of garlic (1.3% allicin) were administered intravenously. The VFT and ULV were determined again at the end of garlic infusion. In group 3 (n = 7), 100 mL of normal saline was administered instead of garlic. Results: The VFT values in groups 1 and 2 were not different from the control VFT. The ULV in group 1 was not different from the control ULV. However, the ULV in group 2 (328  58 V, 8  3 J) was significantly lower than the control ULV (415  24 V, 13  2 J), thus accounting for the reduction of 21% by peak voltage and 38% by energy. The effective refractory period and diastolic pacing threshold were not altered after garlic infusion. Saline did not alter VFT or ULV. Conclusion: Garlic cannot alter the VFT, but it significantly decreases the ULV in a dose- dependent pattern, indicating that it can reduce the range of the stimulation strength between the VFT and ULV (vulnerability window) during the vulnerable period of a cardiac cycle. © 2008 Elsevier Inc. All rights reserved. Keywords: Garlic; Ventricular fibrillation; Arrhythmia; Sudden death; Heart Introduction The high mortality rate from sudden cardiac death, mainly caused by ventricular fibrillation (VF), is a major problem in national health worldwide [1– 4]. Electrical defibrillation is the only successful clinical therapy available for the resuscitation of patients with VF [1,2]. Understanding the basic mechanisms of defibrillation and the high defibrillation efficacy are greatly needed for successful therapies. Herbs have been used for medical treatment since the beginning of human civilization. With the high prevalence of herbal use in Eastern traditional medicines and Western medicinal drugs, garlic was found to have many significant cardiovascular effects. In the past few decades, garlic has been found to act as a significant antiarrhythmic agent, partly due to its free radical scavenging activity [5,6]. Garlic powder has been shown to reduce ischemia reperfusion– induced VF in isolated perfused rat heart [5,7]. Furthermore, garlic dialysate has been shown to suppress premature ven- tricular contraction and ventricular tachycardia in ouabain- intoxicated dogs and ectopic rhythms induced by isoprena- line and aconitine on electrically driven left rat atria, with a significant prolongation of the effective refractory period (ERP) [8]. These findings are possibly caused by garlic’s inhibitory effect in relation to calcium availability in cardiac myocytes [8,9]. Recently, garlic powder has been shown to significantly improve the defibrillation efficacy in a dose- dependent pattern [10]. This study was supported by the Faculty of Medicine Endowment Fund, Chiang Mai University, Chiang Mai, Thailand (R.S. and N.C.), and grants TRF RMU 4980001 (N.C.) and RMU 4880013 (S.C.) from the Thailand Research Fund. * Corresponding author. Tel.: +66-53-945-329; fax: +66-53-945-368. E-mail address: nchattip@mail.med.cmu.ac.th (N. Chattipakorn). Nutrition 24 (2008) 711–716 www.elsevier.com/locate/nut 0899-9007/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.nut.2008.03.003