Potential risk of beta-blockade withdrawal in congestive heart failure due to abrupt autonomic changes.
Beta-Blockers reduce mortality in patients with congestive heart failure and a proposed mechanism has been changes of autonomic tone. Heart rate variability is a non-invasive tool to estimate cardiac autonomic tone. The aim was to study changes of heart rate variability in patients with congestive heart failure on placebo, on the beta1-selective antagonist metoprolol or 24 h after metoprolol withdrawal. Forty-five patients with congestive heart failure were studied with Holter recordings. Heart rate variability measurements were performed before, after 6-12 months of treatment with 150 mg metoprolol/placebo, or 24 h after discontinued metoprolol. After treatment, patients on beta-blockade had a significantly longer mean RR interval and changes of heart rate variability, suggesting elevated vagal tone. Patients monitored in the rebound phase of beta-blocker withdrawal had a significant vagal reduction to the level of the placebo group. There was also a nonsignificant trend towards increased sympathetic tone (LF/HF over 24 h), compared with the beta-blockade group. Heart rate variability indicates an elevated vagal tone during treatment with metoprolol but beta-blockade withdrawal shifts the autonomic balance towards lower vagal and higher sympathetic tone within 24 h. These results could imply a potential risk when abruptly discontinuing beta-blockade medication in these patients.
Tygesen
H
H
Department of Medicine, Borås County Hospital, Sweden. hans.tygesen@mailbox.swipnet.se
Andersson
B
B
Di Lenarda
A
A
Rundqvist
B
B
Sinagra
G
G
Hjalmarson
A
A
Waagstein
F
F
Wennerblom
B
B
D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000009:adverse effects*; D000328:Adult; D000368:Aged; D015716:Electrocardiography, Ambulatory / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000188:drug therapy / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000009:adverse effects*; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000139:chemically induced / Q000503:physiopathology; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology*; D014630:Vagus Nerve / Q000187:drug effects / Q000503:physiopathology*; D014693:Ventricular Fibrillation / Q000139:chemically induced / Q000503:physiopathology
D000319:Adrenergic beta-Antagonists; D008790:Metoprolol