Differential effects of adrenergic antagonists (Carvedilol vs Metoprolol) on parasympathetic and sympathetic activity: a comparison of measures.

Content Provider	Europe PMC
Author	Vinik, Aaron I. Bloom, Heather L. Colombo, Joe
Copyright Year	2014
Abstract	Background Cardiovascular autonomic neuropathy (CAN) is recognized as a significant health risk. Specific and sensitive measures of CAN are needed for early identification and treatment to avoid complications, preferably in the preclinical state. Objectives In this first of two articles, the patient cohort is described and two measures of autonomic function are reviewed: the traditional heart rate variability (HRV)-alone method and the newer parasympathetic and sympathetic (P&S) Method. These systems are then evaluated against known effects of the alpha/beta-adrenergic blocker, Carvedilol, and the selective beta-adrenergic blocker, Metoprolol, on P&S activity. Methods 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. HRV-alone parameters are computed according to standards. The P&S Method, which is a time–frequency analyses of concurrent respiratory activity and HRV, is elucidated, as developed at MIT and Harvard Medical School (1981). Results The HRV-alone demonstrated that introducing either medication increased low frequency (msec2) and standard deviation of the beat-to-beat (N-N) interval (msec), as expected. The other HRV parameter responses were not consistent with expectations. Similar inconsistencies occurred when either medication was discontinued. The P&S Method demonstrated that introducing or discontinuing either agent decreased or increased sympathetic activity, respectively, according to expectations. With ongoing treatment, resting parasympathetic activity decreased with Metoprolol but increased with Carvedilol. Conclusion Autonomic assessment fidelity was significantly higher with the P&S Method as validated by comparison with previously known physiology of the cardiovascular system.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC4774948&blobtype=pdf
ISSN	18261868
Volume Number	9
PubMed Central reference number	PMC4774948
Issue Number	1
PubMed reference number	27004091
Journal	Heart International [Heart Int]
e-ISSN	20362579
Language	English
Publisher	Wichtig
Publisher Date	2014-01-01
Access Restriction	Open
Rights License	© 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 Copyright © 2014, Wichtig Publishing
Subject Keyword	Beta-blocker Cardiac autonomic neuropathy Heart rate variability Patient outcomes Respiratory analysis Sympathovagal imbalance
Content Type	Text
Resource Type	Article
Subject	Cardiology and Cardiovascular Medicine