NEW YORK (Reuters Health) – Beta-blocker-induced heart rate lowering has been shown to have beneficial effects in patients with MI and heart failure, but findings from a new review study indicate that this is not the case in patients with hypertension.

An analysis of data from nine randomized trials, featuring over 68,000 hypertensive patients, shows that heart rate lowering with beta-blockers increases the risks of all-cause death, cardiovascular death, MI, stroke, and heart failure (p < 0.0001 for all). Dr. Franz H. Messerli, from Columbia University in New York, and colleagues speculate that “pharmacologically induced bradycardia may lead to dyssynchrony between outgoing and reflected pulse wave, thereby increasing central aortic pressure and the hemodynamic burden to the target organs.” As reported in the October 28 issue of the Journal of the American College of Cardiology, the investigators searched MEDLINE, EMBASE, and CENTRAL databases for relevant studies released from 1966 to May 2008. A total of 22 randomized controlled trials were identified, of which 9 included heart rate data. All told, 34,096 patients received beta-blockers, 30,139 received other antihypertensive agents, and 3987 received placebo. Beta-blocker-treated patients achieved lower heart rates than did other patients and, as noted, this heart rate lowering was linked to adverse cardiovascular events. Moreover, the slower the heart rate, the greater the risk of these events. In an accompanying editorial, Dr. Norman M. Kaplan, from the University of Texas Southwestern Medical Center in Dallas, comments that the present research “adds another post-mortem explanation for the fall of beta-blockers, showing higher mortality associated with the slower heart rate they induce.” He adds that “with this addition to the evidence, beta-blockers will surely remain as indicated for heart failure, for after MI, and for tachyarrhythmias, but no longer for hypertension in the absence of these compelling indications.” Reference:
J Am Coll Cardiol 2008;1482:1482-1491.