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Long-term carvedilol therapy increases parasympathetic nervous system activity in chronic congestive heart failure
R L Goldsmith1, J T Bigger, D M Bloomfield
1Division of Circulatory Physiology, Columbia University, College of Physicians and Surgeons, New York, New York, USA.
Insights
Beta blockers like carvedilol significantly enhance parasympathetic nervous system activity in patients with heart failure. This study shows increased heart rate variability, indicating improved autonomic function after carvedilol treatment.
Area of Science:
- Cardiology
- Autonomic Nervous System Research
- Pharmacology
Background:
- Congestive heart failure (CHF) is associated with impaired autonomic function.
- Beta-blocker therapy is a cornerstone in managing CHF, but its specific effects on parasympathetic activity require detailed assessment.
Purpose of the Study:
- To investigate the impact of carvedilol, a beta blocker, on parasympathetic nervous system activity in patients with congestive heart failure.
Main Methods:
- Utilized 24-hour Holter monitoring to assess heart rate variability (RR variability).
- Analyzed high-frequency power, root-mean-square of successive differences, and percentage of successive RR interval differences.
- Compared these metrics before and after 3-4 months of carvedilol treatment in 10 CHF patients.
Main Results:
- Significant increases were observed in high-frequency power (26 to 64 ms2, p <0.01).
- Root-mean-square of successive differences increased notably (14.3 to 23.7 ms2, p <0.01).
- The percentage of successive RR interval differences >50 ms rose from 0.8% to 4.7% (p <0.01).
Conclusions:
- Carvedilol treatment leads to a substantial increase in parasympathetic modulation of heart rate intervals in CHF patients.
- These findings suggest improved autonomic balance with carvedilol therapy.
- Beta-blockade with carvedilol enhances vagal tone, a beneficial effect in heart failure management.
Abstract:
To determine the effect of beta blockade on parasympathetic nervous system activity, we assessed RR variability during 24-hour Holter monitoring in 10 patients with congestive heart failure before and after 3 to 4 months of treatment with the beta blocker carvedilol. High-frequency power increased from 26 to 64 ms2, root-mean-square of successive differences in RR interval increased from 14.3 to 23.7 ms2, and percentage of absolute differences >50 ms between successive normal RR intervals increased from 0.8% to 4.7%, all p <0.01, indicating a substantial increase in parasympathetic modulation of RR intervals.