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The treatment of supraventricular arrhythmia include wide range of medical intervention, but ideal drug for treatment of this kind of arrhythmia is yet to be developed. Pharmacological interventions due to their adverse side effects and the possibility of proarrhythmic effects are usually ineffective in treating these conditions. Herbal remedies are suitable alternatives for synthetic drugs, due to their availability, minimal side effects and lower price. Pharmacological studies and traditional medical literature point to the cardiovascular effects of the Achillea Santolina in many instances. In present study, we used isolated heart of langandrof rats as an experimental model to determine the effect of various concentrations of the methanol extract of Achillea santolina (2×10^-7, 2×10^-9, 2×10^-10 W/V) on the electrophysiological properties of the isolated heart. Results of this study show a significant depression of WBCL, AVCT and ERP and non-significant increased in time constant of recovery (trec). It may be therefore be considered a potential role for anti-arrhythmic effect of Achillea Santolina in suppression or treating supraventricular tachyarrhythmia.