Potential risk of beta-blockade withdrawal in congestive heart failure dueto abrupt autonomic changes

beta-Blockers reduce mortality in patients with congestive heart failure an d a proposed mechanism has been changes of autonomic tone. Heart rate varia bility is a non-invasive tool to estimate cardiac autonomic tone. The aim w as to study changes of heart rate variability in patients with congestive h eart failure on placebo, on the beta(1)-selective antagonist metoprolol or 24 h after metoprolol withdrawal. Forty-five patients with congestive heart failure were studied with Holter recordings. Heart rate variability measur ements were performed before, after 6-12 months of treatment with 150 mg me toprolol/placebo, or 24 h after discontinued metoprolol. After treatment, p atients on beta-blockade had a significantly longer mean RR interval and ch anges of heart rare variability, suggesting elevated vagal tone. Patients m onitored in the rebound phase of beta-blocker withdrawal had a significant vagal reduction to the;level of the placebo group, There was also a nonsign ificant trend towards increased sympathetic tone (LF/HF over 24 h), compare d with the beta-blockade group. Heart rate variability indicates an elevate d vagal tone during treatment with metoprolol but beta-blockade withdrawal shifts the autonomic balance towards lower vagal and higher sympathetic ton e within 24 h. These results could imply a potential risk when abruptly dis continuing beta-blockade medication in these patients. (C) 1999 Elsevier Sc ience ireland Ltd, All rights reserved.