TUESDAY, Nov. 7, 2006 (HealthDay News) -- A different kind of heart failure, in which the heart malfunctions only under stress, is more common than has been thought, new research indicates.
Heart failure usually is defined as the progressive loss of the ability to pump blood -- a steady decline in "ejection fraction," the amount of blood expelled in the contraction called systole.
But when cardiologists at the Mayo Clinic assessed 556 people treated for heart failure, they found that 55 percent of them had normal or near-normal ejection fraction. Some 80 percent had abnormalities of diastole, the relaxing time during which the heart fills with blood. Combined systolic and diastolic malfunction was found in 37 percent of the people, and diastolic malfunction was found in 44 percent.
"What this means is that the practicing physician has to recognize that heart disease is not a disease but a spectrum," said Dr. Veronique L. Roger, a consultant in cardiovascular disease at the Mayo Clinic and a member of the research team.
The study findings are published in the Nov. 8 issue of the Journal of the American Medical Association.
Traditionally, cardiologists have looked for systolic abnormalities in heart-failure patients, Roger said. The new study shows that it can be equally important to diagnose diastolic abnormalities that prevent the heart from filling with blood as it should, she said.
Heart failure with normal ejection fraction requires different treatment, said Dr. Barry Borlaug, a consultant in cardiovascular disease at the Mayo Clinic. He was a member of a team at the Johns Hopkins School of Medicine that drew up a plan for a trial that would insert pacemakers in such patients, speeding cardiac activity rather than slowing it, as drug treatment does.
A pacemaker could allow a patient whose heart falters even under the slightest stress, such as getting dressed, to meet the demands of daily activity, he said.
"This is a major public health problem," Borlaug said. "Half of all heart-failure patients have preserved ejection fraction. There is not much in the way of proven therapies for it. The Roger study shows that mortality for both conditions is the same, about 6 percent in the course of the study."
Another report in the same issue of the journal emphasized the importance of systolic blood pressure, the higher number in a blood-pressure reading. People hospitalized for heart failure who had low systolic pressure were much more likely to die than those with higher systolic readings, the study found.
It was a large study, using data on more than 48,000 people treated for heart failure at 259 U.S. hospitals. It found that the odds of dying in a hospital increased 21 percent for each 10-millimeter drop in systolic blood pressure. The in-hospital death rate was 7.2 percent for patients with systolic pressure under 120, 3.6 percent for those with readings between 120 and 139, and 2.5 percent for readings between 140 and 161.
"What the results imply is that patients with systolic blood pressure under 120 clearly require more intensive monitoring and more intensive therapy both in and out of the hospital," said Dr. Gregg C. Fonarow, professor of cardiovascular medicine and science at the University of California, Los Angeles, and a member of the research team. "They remain at high risk for 60 to 90 days after discharge."
The study indicates that these patients require more aggressive use of heart-failure drugs such as ACE inhibitors and beta blockers, Fonarow said, but that "they are less likely to be treated with these agents."
"We need further research on improving the outcome for patients hospitalized for heart failure with low systolic pressure," he said.
To learn more about heart failure and its treatments, visit the American Heart Association.