Author + information
- Received March 12, 1992
- Revision received August 21, 1992
- Accepted August 24, 1992
- Published online March 1, 1993.
- Philip F. Binkley, MD, FACC∗,1,
- Garrie J. Haas, MD,
- Randall C. Starling, MD, FACC,
- Enrico Nunziata, MSBME,
- Patricia A. Hatton, CNMT,
- Carl V. Leier, MD, FACC and
- Robert J. Cody, MD, FACC
- ↵∗Address for correspondence: Philip F. Binkley, MD, Ohio State University Hospital, Room 610 Means Hall, 1654 Upham Drive, Columbus, Ohio 43210.
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 survivel 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.
↵1 Dr. Binkley is the recipient of a Clinical Associate Physician Award from the National Institutes of Health, Bethesda, Maryland.
☆ This study was presented in part at the 40th Annual Scientific Session of the American College of Cardiology, Atlanta, Georgia, March 1991. This study was supported in part by the Seward Schooler Family Foundation, Columbus, Ohio and in part by Bristol-Myers Squibb Company, Princeton, New Jersey.
- Received March 12, 1992.
- Revision received August 21, 1992.
- Accepted August 24, 1992.