by Lynn Shapiro
, Writer | January 21, 2009
The severity of first heart attacks has dropped significantly in the United States -- propelling a decline in coronary heart disease deaths, researchers reported in Circulation: Journal of the American Heart Association.
"This landmark study suggests that better prevention and better management in the hospital have contributed to the reduction in deaths," said Merle Myerson, M.D., Ed.D., lead author of the study, cardiologist and director of the Cardiovascular Disease Prevention Program at St. Luke's-Roosevelt Hospital of Columbia University in New York City.
"Better control of risk factors for heart disease, such as blood pressure and cholesterol as well as improvements in hospital management may lessen the severity if somebody has a heart attack," Myerson said. "We also considered whether people had less severity because they got to the hospital sooner, but that was not the case."
The study extends previous findings from the Atherosclerosis Risk in Communities (ARIC), an ongoing epidemiologic study that includes data from four areas - Forsythe County, N.C., including Winston-Salem; Washington County, Md., including Hagerstown; and the suburbs of Minneapolis, Minn. and Jackson, Miss. Both whites and African-Americans were included in the study.
In a previous analysis of ARIC data gathered from 1987 to 1994, researchers found a decrease in many, but not all indicators of severity. Myerson and colleagues included an extra eight years of data, covering 10,285 patients, ages 35 to 74, who were discharged from the hospital diagnosed with a definite or probable first-time heart attack from Jan. 1, 1987 through Dec. 31, 2002. The new findings show a more consistent picture with a clear decline in severity of heart attacks.
Researchers assessed severity based on patients' electrocardiogram (ECG) findings, the levels of enzymes in the blood associated with heart muscle damage and hemodynamic abnormalities related to blood flow and blood pressure.
Adjusted for age, sex and race, the new findings included:
- A significant drop occurred in the proportion of patients who had major ECG abnormalities, including an average 1.9 percent per year decline in initial ST-segment elevation, a 3.9 percent decline per year for a new (subsequent) Q-wave, and 4.5 percent per year decline for any major Q-wave.
- The average percentage of patients with abnormal biomarkers dropped 0.7 percent, a modest but statistically significant decline.
- Hemodynamic factors (forces involved in blood circulation) showed mixed results. For example, the percentage of patients with cardiogenic shock dropped 5.7 percent per year. But the proportion with systolic blood pressure of 100 mm Hg or less was unchanged, and the percentage with an abnormal pulse rate - less that 60 or more than 100 beats per minute - increased moderately.