title: Evaluation of Melissa officinalis (Lemon Balm) Effects on Heart Electrical System.
abstract: BACKGROUND
  Melissa officinalis, an herbal drug, is well known and frequently applied in traditional and modern medicine. Yet, there is inadequate information regarding its effects on electrical properties of the heart. The present study attempted to elucidate the effects of Melissa officinalis aqueous extract on electrocardiogram (ECG) in rat.
  
  
  OBJECTIVE
  ECG is an easy, fast and valuable tool to evaluate the safety of used materials and drugs on heart electrical and conductivity properties. Many drugs with no cardiovascular indication or any overt cardiovascular effects of therapeutic dosing become cardiotoxic when overdosed (16). On the other hand, there are numerous substances and drugs that can cause ECG changes, even in patients without a history of cardiac disease. Therefore, this study was conducted to elucidate safety and outcome of one-week administration of M. officinalis aqueous extract on blood pressure and ECG parameters of rats.
  
  
  METHODS
  Four animal groups received tap water (control group), aqueous extracts of Melissa officinalis 50 (M50), 100 (M100) and 200 (M200) mg/kg/day, respectively and orally for a week. ECG and blood pressure were recorded on the eighth day of experiment.
  
  
  RESULTS
  Consumption of Melissa officinalis extract associated with prolonged QRS interval (P < 0.05 for M50 and M100 groups and P < 0.01 for M200 group versus the control group, respectively), prolonged QTc and JT intervals (P < 0.01 for different M groups versus the control group) and prolonged TpTe interval (P < 0.001 when M groups compared with the control group) of ECG. However, different doses of the extract had no significant effect on RR interval, PR interval, amplitudes of ECG waves, heart rate and blood pressure.
  
  
  CONCLUSIONS
  For the first time, this study revealed that consumption of Melissa officinalis extract is associated with significant ECG alterations in rat. Future studies are necessary to determine potential clinical outcomes.
authors.affiliation: Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, IR Iran ; Department of Physiology and Pharmacology, School of Medicine, Kerman University of Medical Sciences, Kerman, IR Iran.
authors.forename: Siyavash
authors.initials: S
authors.lastname: Joukar
authors.affiliation: Department of Physiology and Pharmacology, School of Medicine, Kerman University of Medical Sciences, Kerman, IR Iran.
authors.forename: Haleh
authors.initials: H
authors.lastname: Asadipour
keywords: Blood Pressure; Electrocardiography; Melissa officinalis