Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Exercise stress testing helps identify people at risk of developing coronary heart disease

13.09.2005


Testing for exercise capacity and heart rate recovery improves on traditional risk-factor scoring

Performing cardiac stress tests that measure exercise capacity and heart rate recovery can improve dramatically on existing techniques that predict who is most likely to suffer a heart attack or die from coronary heart disease (CHD), the leading cause of death in the United States, a team of cardiologists at Johns Hopkins reports.

In the Sept. 13 edition of the journal Circulation, the Hopkins team reports that 90 percent of men and women with no early signs of CHD who, nevertheless, died from it had had below average results from their cardiac stress tests conducted 10 to 20 years earlier.



The team’s analysis showed these asymptomatic people were two to four times more likely to die from CHD within 10 to 20 years than people with average or better-than-average stress test results, even though traditional scoring for major risk factors for the disease, such as such as age, blood pressure, blood cholesterol levels and smoking status, had determined the asymptomatic people to be at low or intermediate risk of having heart problems.

According to the cardiologists, these exercise stress tests are easy to perform, lasting less than 20 minutes and requiring only that a person walk on a treadmill at progressively higher speeds and inclines every three minutes until they become markedly fatigued. During the test, people are hooked up to a heart monitor.

"This is the strongest evidence to date that selective use of cardiac stress testing improves prediction of who is really at high risk of suffering a fatal heart attack when traditional risk assessment suggests they are not at high risk of a heart attack within the next 10 years," says senior study author and cardiologist Roger S. Blumenthal, M.D., an associate professor and director of the Ciccarone Preventive Cardiology Center at The Johns Hopkins University School of Medicine and its Heart Institute.

The traditional risk factors combine to give a score called the Framingham Risk Score, or FRS, that was developed in the last 20 years. Considered the gold standard, the score is based on a summary estimate of the major risk factors for heart disease: age, blood pressure, blood cholesterol levels and smoking status. It consists of a percentage range of how likely a person is to suffer a fatal or nonfatal heart attack within 10 years.

However, Blumenthal says that many people, especially women, with cardiovascular problems go undetected despite use of the Framingham score, which does not factor in a person’s family history, weight or exercise habits. Blumenthal is also a spokesman for the American Heart Association, which estimates that 656,000 Americans died from CHD in 2002, the last year for which statistics are available.

More than 6,100 people took part in the study, conducted from 1972 to 1995, and part of a larger project known as the Lipid Research Clinics Prevalence Study. All participants in this smaller Hopkins study were age 30 to 70. None had early signs of heart disease, but every participant did have at least one major risk factor for it.

At 10 medical centers across the United States, study participants were given a physical examination, had blood tests performed and were scored on the FRS. Each participant also underwent cardiac stress testing, which included stress testing for exercise capacity and heart rate recovery, plus any changes in the heart’s electrical signaling that are typical of decreased blood flow to the heart muscle.

Those with a Framingham score of less than 10 percent were gauged to be at low risk for future CHD, while participants with a score between 10 percent and 20 percent were ranked at intermediate risk for future CHD, and those with a score higher than 20 percent were judged to be at high risk of CHD.

Once participants were ranked by Framingham score, the researchers monitored their health every six months until death or the end of the study to find out who did or did not die from a heart attack or CHD.

Cardiac stress testing is used to gauge how well the heart works when it has to pump harder and use more oxygen, for example, while walking on a treadmill. The exercise, sustained for five to 10 minutes, mimics the strain placed on the heart when arteries are blocked or narrowed.

The researchers goal, however, was to determine if more accurate prediction of whether or not a person will die from a heart attack could be made by adding exercise capacity and heart rate recovery to current assessment techniques that relied mostly on monitoring the heart’s electrical signaling.

During stress testing, a person’s breathing, blood pressure and heart rate are monitored while the intensity of their exercising is slowly increased to see how their heart responds. The amount, in number of beats per minute that the heart rate drops two minutes after exercise stops, is also recorded to determine heart rate recovery.

Using tables that take into account a person’s age, gender and weight, the results can be compared against average scores to see if a person is below, at or above the norm. There is very little risk of harm associated with the testing because participants are closely monitored.

The researchers report that 246 participants died from CHD even though they had initially been categorized by their FRS as at either low or intermediate risk of the disease. However, 225 of those who died also had below average test scores for exercise capacity and heart rate recovery.

"Our best means of preventing coronary heart disease is to identify those most likely to develop the condition and intervene before symptoms appear," says the study’s lead author, cardiologist Samia Mora, M.D., M.H.S., then a research fellow at Hopkins.

"Cardiac stress testing could significantly improve our abilities to find and aggressively treat these people so that they are much less likely to suffer a heart attack."

According to the researchers, these latest results support conclusions from earlier this year that traditional risk assessment with the FRS can be improved with selective use of cardiac CT scans to measure calcium scores in individuals with more than one risk factor, such as obesity, smoking, sedentary lifestyle or a family history of heart disease.

David March | EurekAlert!
Further information:
http://www.jhmi.edu

More articles from Health and Medicine:

nachricht Penn studies find promise for innovations in liquid biopsies
30.03.2017 | University of Pennsylvania School of Medicine

nachricht 'On-off switch' brings researchers a step closer to potential HIV vaccine
30.03.2017 | University of Nebraska-Lincoln

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>