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Enlarged heart may lead to heart attacks

/ Source: The Associated Press

Aggressively lowering blood pressure isn’t enough to prevent heart attacks and strokes in some patients, and now researchers think they know one reason: enlargement of the heart’s main pumping chamber.

The condition is called left ventricular hypertrophy, or LVH, and affects at least 20 percent of Americans with high blood pressure, or up to 12 million people.

Two new studies found that reducing LVH with blood-pressure drugs can further lower the risk of deadly heart trouble in patients whose blood pressure already has been substantially reduced.

“We’ve always known that lowering blood pressure alone in hypertensive patients did not completely reduce the increased risks,” said Dr. Peter Okin of Weill Cornell Medical College in New York. “The question was why.”

The findings confirm doctors’ suspicions that persistent LVH is at least partly to blame, said Okin, who led one of the studies. Another Weill Cornell researcher, Dr. Richard Devereux, led the other. Both appear in Wednesday’s Journal of the American Medical Association.

LVH often is not thought of as a standard risk factor for heart attacks and strokes — partly because, until now, there has been relatively little data showing that reversing LVH could make a difference, according to a JAMA editorial.

Regular LVH tests suggested

Hypertension is the most common cause of LVH, and Okin said all patients with high blood pressure probably should be tested for LVH periodically throughout treatment — something many doctors do not routinely do, he said. Patients whose LVH is not improving or is getting worse should be treated more aggressively, he said.

But American Heart Association spokesman Dr. Daniel Jones contended routine repeat tests to assess LVH in patients with high blood pressure would be premature and too costly. The independent effects of reducing LVH were small in the two studies, and reducing patients’ blood pressure should remain the top priority, Jones said.

Okin and Devereux have been paid consultants for Merck & Co., makers of one of the blood pressure drugs involved in the two studies. Merck partly funded both studies.

The studies stem from research on 9,193 men and women with high blood pressure treated with either Merck’s Losartan or the beta blocker atenolol.

In one study, Okin assessed rates of heart attacks, strokes and related deaths over an average of nearly five years. LVH was measured annually by electrocardiograms — inexpensive and widely available tests that measure electrical impulses in the heart.

Patients whose tests showed significant LVH shrinkage were 29 percent less likely to have cardiovascular-related deaths and nonfatal heart attacks and strokes than those whose LVH was unchanged.

Devereux found similar results in a subset of patients evaluated with echocardiograms — a more expensive test that uses sound waves to measure the heart.