Hypertension Plus Tachycardia Equals High Risk

An elevated resting heart rate is associated with an increased risk of cardiac events in high-risk hypertension, according to a secondary analysis of a large randomized trial.

Among patients randomized to two different antihypertensives, each 10 beats per minute increase in baseline heart rate was associated with a relative 16% greater risk of cardiovascular mortality and morbidity (P<0.0001), according to Stevo Julius, MD, ScD, of the University of Michigan in Ann Arbor.

The relationship remained significant (P<0.0001) even among those patients who had their blood pressure controlled to less than 140/90 mm Hg (average 130/77 mm Hg), Julius reported at the American Society of Hypertension meeting here.

"In all diseases of civilization it has been shown that lowering of cardiovascular risk components - glucose, lipids, blood pressure - decreases cardiovascular events," he said. "So we are saying that we see no reason why lowering the heart rate should not also be beneficial."

Julius said hypertension guidelines should recognize tachycardia as a potent and clinically relevant cardiovascular risk factor.

Agreeing was Franz Messerli, MD, director of the hypertension program at St. Luke's-Roosevelt Hospital Center in New York City.

"We have known for quite some time that heart rate is a neglected risk factor for cardiovascular disease," said Messerli, an officer of ASH.

He pointed out, however, that lowering heart rate has not always improved outcomes.

"So we are in a kind of paradoxical situation where we clearly know a high heart rate is no good, but lowering heart rate by pharmacologic therapy is not always beneficial."

Julius said there was an increasing interest in the relationship between heart rate and mortality, as reflected in a greater number of research papers addressing the issue.

To explore the impact of heart rate on outcomes, he and his colleagues conducted an analysis of data from the VALUE trial, which included 15,245 patients with high-risk hypertension from 30 countries.

The trial compared the rate of composite cardiovascular mortality and morbidity, the primary endpoint, between an amlodipine- or valsartan (Diovan)-based treatment. As reported in 2004, there was no significant difference between the two groups.

For the purposes of the current analysis, all of the patients were pooled together.

An increase in heart rate of 10 bpm from baseline was not only associated with the composite cardiovascular endpoint, but with the individual components of heart failure (HR 1.25), sudden cardiac death (HR 1.20), myocardial infarction (HR 1.09), and stroke (HR 1.12). All were significant at P<0.05.

Adjusting for baseline blood pressure and other cardiovascular risk factors did not substantially change the results.