The severity of heart attacks in the United States is apparently declining, a Wake Forest University School of Medicine researcher told the American Heart Association today. Possible reasons for the decline include increased preventive measures and better treatment for heart attacks.
David C. Goff Jr., M.D., Ph.D., said results from previous analyses of the long-running Atherosclerosis Risk in Communities (ARIC) study show that both in-hospital and out-of-hospital coronary heart disease mortality decreased between 1987 and 1994, paralleling national and international statistics.
Goff, associate professor of public health sciences (epidemiology) focused his analysis on whether severity of heart attacks was declining.
He told the Heart Association''s Conference on Cardiovascular Disease Epidemiology and Prevention in Orlando that analysis of a number of heart attack indicators supports the contention that the average size of the infarct — the area of heart muscle damaged by the heart attack — decreased over the study period. The smaller the affected area, the smaller the resulting disability.
"These changes may be due to preventive efforts or to improvements in acute treatments," he said. "Primary prevention efforts, like blood pressure and cholesterol control, may have led to lower severity of heart attacks when heart attacks occur."
The widely reported ARIC cohort study involves about 16,000 randomly selected participants in Forsyth County, N.C., Jackson, Miss., Hagerstown, Md. and suburban Minneapolis, Minn. But a second community surveillance component of ARIC involves complete recording of all heart attacks and coronary heart disease mortality in each ARIC community.
Goff studied records of patients between ages 35 and 74 in the ARIC communities who had definite or probable heart attacks between Jan. 1, 1987, and Dec. 31, 1994. Of the 8,807 cases, he focused on 4903 first heart attacks. Of these, 71.7 percent met the criteria for a definite (as opposed to a probable) heart attack. But that percentage actually was decreasing over the course of the study.
During the study, two of three indicators that were based on the electrocardiograms showed an increase in severity.
However, a different kind of measure based on enzymes in the blood that confirm heart attacks showed declining severity, despite the development of more sensitive measurements.
A third kind of measure, based on whether patients had an abnormal pulse rate, or had an abnormally low systolic blood pressure (the first number of the two in the typical blood pressure statement), showed little change.
Thus, he said, the results from the severity indicators "are somewhat inconsistent," but as a whole, they point to a lessening in the severity of hospitalized heart attack patients.
He said the findings support the combined roles of preventive efforts and acute medical care in reducing coronary heart disease mortality.
"Continued commitment of resources to research and development in these areas, to the implementation of new knowledge into medical practice and to the monitoring of these trends through high quality surveillance activities is justified in the ongoing effort to reduce the human suffering and financial burden associated with coronary heart disease in the United States," Goff said.
"Some of these prevention efforts are paying off."
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