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Author Notes:

Address for correspondence: Dr. Joe Colombo, 240 South Eighth Street, Philadelphia, PA, USA 19107, joe@ans-hrv.com

Conflict of interest: Drs. Bloom and Vinik are unpaid advisors to ANSAR. Dr. Colombo is Medical Director of ANSAR.



  • Beta-blocker
  • Cardiovascular autonomic neuropathy
  • Heart rate variability
  • Patient outcomes
  • Respiratory analysis
  • Sympathovagal imbalance
  • Cardiology

Differential effects of adrenergic antagonists (Carvedilol vs Metoprolol) on parasympathetic and sympathetic activity: A comparison of clinical results


Journal Title:

Heart International


Volume 9, Number 1


, Pages 15-21

Type of Work:

Article | Final Publisher PDF


Background: Cardiovascular autonomic neuropathy (CAN) is recognized as a significant health risk, correlating with risk of heart disease, silent myocardial ischemia or sudden cardiac death. Beta-blockers are often prescribed to minimize risk. Objectives: In this second of two articles, the effects on parasympathetic and sympathetic activity of the alpha/ beta-adrenergic blocker, Carvedilol, are compared with those of the selective beta-adrenergic blocker, Metoprolol. Methods: Retrospective, serial autonomic nervous system test data from 147 type 2 diabetes mellitus patients from eight ambulatory clinics were analyzed. Patients were grouped according to whether a beta-blocker was (1) introduced, (2) discontinued or (3) continued without adjustment. Group 3 served as the control. Results: Introducing Carvedilol or Metoprolol decreased heart rate and blood pressure, and discontinuing them had the opposite effect. Parasympathetic activity increased with introducing Carvedilol. Sympathetic activity increased more after discontinuing Carvedilol, suggesting better sympathetic suppression. With ongoing treatment, resting parasympathetic activity decreased with Metoprolol but increased with Carvedilol. Conclusion: Carvedilol has a more profound effect on sympathovagal balance than Metoprolol. While both suppress sympathetic activity, only Carvedilol increases parasympathetic activity. Increased parasympathetic activity may underlie the lower mortality risk with Carvedilol.

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© 2014 The Authors. This article is published by Wichtig Publishing and licensed under Creative Commons Attribution-NC-ND 4.0 International CC BY-NC-ND 4.0). Any commercial use is not permitted and is subject to Publisher’s permissions. Full information is available at www.wichtig.com.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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