Abstract: AIM: To investigate whether transdermal scopolamine increased cardiac vagal activity in patients with acute myocardial infarction. METHODS: A random, double blind, and placebo contrast trial was performed.Measures of heart rate variability (HRV) in patients given drugs or placebo were obtained by electrocardiograph and digital 24 hHolter recording before and after treatment.Baroreflex sensitivity (BRS) was performed using the phenylephrine method. RESULTS: Patients of acute myocardial infarction with transdermal scopolamine showed a significant increase in HRV time domain parameters and BRS after treatment (P <0.05). CONCLUSION: Low doses of transdermal scopolamine increased cardiac vagal activity improves autonomic indices in patients with acute myocardial infarction.

Key words: myocardial infarction, acute, vagus, scopolamine, heart rate variability, baroreflex sensitivity