by Will Boggs, MD
Last Updated: 2007-08-30 13:06:21 -0400 (Reuters Health)
NEW YORK (Reuters Health) – Higher resting heart rates are associated with an increased risk of cardiovascular disease, according to a review in the August 28th Journal of the American College of Cardiology.
"I hope that as a consequence of the article physicians consider why a healthy person has a high heart rate and search for causes, such as anemia, thyrotoxicosis, etc.," Dr. Kim Fox told Reuters Health. "In an otherwise healthy person, I think we are a long way off suggesting pharmacological intervention to improve outcome."
Dr. Fox from Royal Brompton Hospital, London, and colleagues reviewed the data associating resting heart rate and mortality, the possible pathophysiological basis of this association, and the likelihood utility of therapeutic heart rate slowing in improving cardiovascular outcomes for a wide range of patients.
Epidemiological data regarding both the general population and patients with various cardiovascular diseases reveal significant associations between resting heart rate and all-cause and cardiovascular mortality, the authors report.
Lowering of resting heart rate, they note, has proven beneficial in preventing exercise-induced angina and ischemia and reducing mortality in patients with coronary artery disease and with heart failure.
Heart rate appears to have direct effects on the status of the arterial wall, the investigators say, as a result of mechanical pulsatile stress and possibly through proinflammatory actions of such stresses on the vascular endothelium. Heart rate also influences whether ischemic episodes trigger serious arrhythmias.
A relatively high heart rate is likely both causative and indicative of important pathophysiological processes, the researchers note, but exactly what heart rate is optimal remains uncertain.
"From the epidemiologic data presented previously," the investigators write, "it seems desirable to maintain heart rate in the normal rather than in the high range, and specifically, to maintain resting heart rate substantially below the traditionally defined tachycardia threshold of 90 or 100 beats per minute."
"We have designed and are running two very large-scale trials in coronary disease with various degrees of left ventricular impairment," Dr. Fox said. "We are looking at the effect of pure heart rate reduction in these patients who are otherwise well, treated with therapies such as beta blockers, ACE inhibitors/ARBs, statins, and aspirin."
"Clearly, if our studies in coronary disease are proven to show that reducing heart rate improves outcome, then this should be introduced into clinical practice," Dr. Fox concluded.
J Am Coll Cardiol 2007;50:823-830.