Explaining trends in heart attack

Mar 11, 2009

Explaining trends in heart attack: prevention has improved, mortality rates are down, hospitalisation remains the same

A report in Circulation from the Framingham Heart Study, which compared acute (AMI) incidence in 9824 men and women over four decades, has proposed an explanation for the apparent paradox of improved prevention, falling but stable rates of hospitalisation.(1) The study found that over the past 40 years rates of AMI diagnosed by ECG decreased by 50%, whereas rates of AMI diagnosed exclusively by infarction biomarkers doubled. This "evolving" diagnosis of AMI, say the investigators, "offers an explanation for the apparently steady national AMI rates in the face of improvements in primary prevention".

However, the investigators emphasise that this study - like others before it - highlights a "40-50%" reduction in heart disease mortality in the USA from 1968 to 2000 and a 50% decline in the incidence of AMI when diagnosed by ECG. This, they propose, "implies that primary prevention efforts have influenced the incidence of AMI". That the incidence of hospitalised AMI has not similarly declined is explained by the greater sensitivity of diagnostic AMI biomarkers; they note, for example, that the detection rate of AMI by troponin was higher than in earlier decades.

Another explanation for the decline in AMI mortality rates may be found in a second report from the same Circulation issue.(2) A cohort study of more than 13,000 residents of Worcester, USA, hospitalised with AMI found that the incidence of cardiogenic shock, the most common complication of AMI associated with fatality, declined throughout the 30-year study period. "The results of our study suggest that patients hospitalized with AMI in the 2000s were less likely to develop cardiogenic shock than greater Worcester residents hospitalized with AMI during earlier study years," the investigators report. Cardiogenic shock results from failure of the ventricles to provide adequate circulation of blood.

Commenting on behalf of the European Society of Cardiology, Professor Frans Van de Werf, Chairman of the Cardiology Department at the University Hospital, Leuven, Belgium, said: "These papers are indeed very helpful for understanding trends reported in recent epidemiological studies of AMI. The data underline the critical importance of the definition of an AMI. The increasing use of very sensitive and specific markers of myocardial necrosis (troponins) and the acceptance of a 'universal definition' of AMI have certainly influenced its detection and reporting. This also explains the increase in reporting of non-ST-elevations AMI.

"The decrease in hospital mortality in patients with cardiogenic shock in the last decade is most likely due to reperfusion therapy, in particular primary angioplasty. An aggressive approach to these patient is recommended in both the US and European guidelines."

More information:

1. Parikh NI, Gona P, Larson MG, et al. Long-term trends in myocardial infarction incidence and case fatality in the National Heart, Lung, and Blood Institute's Framingham Heart Study. Circulation 2009; 119: 1203-1210.

2. Goldberg RJ, Spencer FA, Gore JM, et al. Thirty-year trends (1975 to 2005) in the magnitude of, management of, and hospital death rates associated with cardiogenic shock in patients with acute myocardial infarction. A population-based perspective. Circulation 2009; 119: 1211-1219.

Source: European Society of Cardiology (news : web)

Explore further: Dallas hospital confirms first Ebola case in US

add to favorites email to friend print save as pdf

Related Stories

AT&T to put 8,000 natural-gas vehicles on road

Mar 11, 2009

(AP) -- AT&T Inc. said Wednesday it will spend up to $350 million over five years to buy more than 8,000 Ford Motor Co. vans and trucks, then convert them to run on compressed natural gas.

Migraines increase stroke risk during pregnancy

Mar 10, 2009

Women who suffer migraines are at an increased risk of stroke during pregnancy as well as other vascular conditions such as heart disease, high blood pressure and blood clots, concludes a study published on bmj.com today.

More evidence prostate tests overdiagnose cancer

Mar 11, 2009

(AP) -- As many as two of every five men whose prostate cancer was caught through a PSA screening test have tumors too slow-growing to ever be a threat, says a new study that raises more questions about the controversial ...

The changing roles of mothers and fathers

Mar 10, 2009

Elvire Vaucher is a professor at the Université de Montréal School of Optometry. Her husband is an artist who works from home. Upon the birth of their second child in 2003, she took only three months maternity ...

Recommended for you

Africa's uneven health care becomes easy prey for Ebola

26 minutes ago

The disparity in African countries' ability to fight Ebola has left the continent fighting an uneven struggle against a disease that doesn't respect borders—yet relatively simple measures could help, experts say.

Ebola case stokes concerns for Liberians in Texas

1 hour ago

The first case of Ebola diagnosed in the U.S. has been confirmed in a man who recently traveled from Liberia to Dallas, sending chills through the area's West African community whose leaders urged caution ...

Is Australia prepared for Ebola?

4 hours ago

Australia needs to be proactive about potential disease outbreaks like Ebola and establish a national centre for disease control.

Dallas hospital confirms first Ebola case in US

9 hours ago

A patient at a Dallas hospital has tested positive for Ebola, the first case of the disease to be diagnosed in the United States, federal health officials announced Tuesday.

User comments : 0