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.
MeSH terms
-
Adrenergic beta-Antagonists / administration & dosage
-
Adrenergic beta-Antagonists / pharmacology*
-
Adrenergic beta-Antagonists / therapeutic use
-
Adult
-
Aged
-
Angiotensin-Converting Enzyme Inhibitors / therapeutic use
-
Carbazoles / administration & dosage
-
Carbazoles / pharmacology*
-
Carbazoles / therapeutic use
-
Carvedilol
-
Chronic Disease
-
Digoxin / therapeutic use
-
Electrocardiography / drug effects*
-
Female
-
Heart Failure / drug therapy*
-
Humans
-
Male
-
Middle Aged
-
Parasympathetic Nervous System / drug effects*
-
Propanolamines / administration & dosage
-
Propanolamines / pharmacology*
-
Propanolamines / therapeutic use
Substances
-
Adrenergic beta-Antagonists
-
Angiotensin-Converting Enzyme Inhibitors
-
Carbazoles
-
Propanolamines
-
Carvedilol
-
Digoxin