85829
document
Sustained augmentation of parasympathetic tone with angiotensin-converting enzyme inhibition in patients with congestive heart failure . OBJECTIVES The objective of this investigation was to evaluate the changes in parasympathetic tone associated with long-term angiotensin-converting enzyme inhibitor therapy in patients with congestive heart failure . BACKGROUND Angiotensin-converting enzyme inhibitors provide hemodynamic and symptomatic benefit and are associated with improved survival in patients with congestive heart failure . Angiotensin II , whose production is ultimately inhibited by these agents , exerts significant regulatory influence on a variety of target organs including the central and peripheral nervous systems . Accordingly , it would be anticipated that angiotensin-converting enzyme inhibitors would significantly alter the autonomic imbalance characteristic of patients with congestive heart failure and that this influence over neural mechanisms of cardiovascular control may significantly contribute to the hemodynamic benefit and improved survival associated with angiotensin-converting enzyme inhibitor therapy . METHODS In the current investigation , changes in autonomic tone associated with long-term administration of an angiotensin-converting enzyme inhibitor were measured using spectral analysis of heart rate variability in 13 patients with congestive heart failure who were enrolled in a double-blind randomized placebo-controlled trial of the angiotensin-converting enzyme inhibitor zofenopril . Both placebo and treatment groups were balanced at baseline study in terms of functional class , ventricular performance and autonomic tone . RESULTS After 12 weeks of therapy with placebo , there was no change in total heart rate variability , parasympathetically governed high frequency heart rate variability or sympathetically influenced low frequency heart rate variability . In contrast , therapy with zofenopril was associated with a 50 % increase in total heart rate variability ( p = 0.09 ) and a significant ( p = 0.03 ) twofold increase in high frequency heart rate variability , indicating a significant augmentation of parasympathetic tone . CONCLUSIONS These results demonstrate that long-term treatment of patients having congestive heart failure with an angiotensin-converting enzyme inhibitor is associated with a restoration of autonomic balance , which derives in part from a sustained augmentation of parasympathetic tone . Such augmentation of vagal tone is known to be protective against malignant ventricular arrhythmias in patients with ischemic heart disease and therefore may have similar benefit in the setting of ventricular failure , thus contributing to the improved survival associated with angiotensin-converting enzyme inhibitor therapy in patients with congestive heart failure .
85830
Intervention_Pharmacological
angiotensin-converting enzyme inhibition
85831
Intervention_Pharmacological
angiotensin-converting enzyme inhibitor therapy
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Intervention_Control
placebo-controlled
85833
Intervention_Pharmacological
angiotensin-converting enzyme inhibitor zofenopril
85834
Intervention_Control
placebo
85835
Intervention_Pharmacological
zofenopril
85836
Intervention_Pharmacological
angiotensin-converting enzyme inhibitor
85837
Outcome_Physical
total heart rate variability
85838
Outcome_Physical
parasympathetically governed high frequency heart rate variability
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Outcome_Physical
sympathetically influenced low frequency heart rate variability
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Outcome_Physical
increase in total heart rate variability
85841
Outcome_Physical
heart rate variability
85842
Participant_Condition
patients with congestive heart failure .
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Participant_Condition
patients with congestive heart failure .