Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New imaging technology reveals prevalence of 'silent' heart attacks

22.04.2009
So-called "silent" heart attacks may be much more common than previously believed, according to researchers at Duke University Medical Center.

Studies show that each year, nearly 200,000 people in the U.S suffer a heart attack but may not realize it. These "silent" heart attacks aren't noted because they don't cause any pain – or at least any pain that patients believe is related to their heart – and they don't leave behind any telltale irregularities on electrocardiograms (ECGs).

New imaging research from Duke University Medical Center appearing in PLoS Medicine suggests that these heart attacks (now called unrecognized myocardial infarctions, or UMIs) may be happening much more frequently than physicians had suspected. Duke investigators also found that these attacks were associated with a surprisingly high risk of untimely death.

"No one has fully understood how often these heart attacks occur and what they mean, in terms of prognosis," says Han Kim, M.D., a cardiologist at Duke and the lead author of the study. "With this study, we can now say that this subset of heart attacks, known as non-Q wave UMIs, is fairly common, at least among people with suspected coronary artery disease."

Physicians can usually tell when a heart attack has recently occurred by signature changes on ECGs and in certain blood enzyme levels. But if a heart attack happened in the distant past, physicians rely on the appearance of a specific alteration on an ECG called a Q-wave, which signals the presence of damaged tissue.

"The problem is, not all UMIs result in Q-waves on the electrocardiogram. Those that don't are called non-Q-wave myocardial infarctions. Those are the ones we haven't been able to count because we've never had a good way to document them," says Kim.

Kim believed that using delayed enhancement cardiovascular magnetic resonance, or DE-CMR, might be good way to get an idea about how frequently non-Q-wave myocardial infarctions occur. Previous studies had shown that DE-CMR was particularly adept in discerning damaged tissue from healthy tissue.

Researchers used DE-CMR to examine185 patients suspected of having coronary artery disease but who had no record of any heart attacks. All of them were scheduled to undergo angiography to find out if excess plaque had narrowed or blocked any of their arteries. Investigators followed the patients for two years to see if the presence of any unrecognized non-Q-wave heart attacks were associated with a higher risk of death.

They found that 35 percent of the patients had evidence of a heart attack and that non-Q-wave attacks were three times more common than Q-wave UMIs. Non-Q-wave attacks were also more common among those with more severe coronary artery disease. In addition, researchers discovered that those who suffered non-Q-wave UMIs had an 11-fold higher risk of death from any cause and a 17-fold higher risk of death due to heart problems, when compared to patients who did not have any heart damage.

"Right now, there are no specific guidelines about how patients with UMIs should be treated," says Kim. "If patients with UMIs happen to be identified, they are usually treated similarly to those patients where heart disease has already been documented. Future studies will likely examine how common unrecognized non-Q-wave heart attacks are in other patient groups and how these UMIs should be treated."

The National Institutes of Health supported the study.

Duke researchers who contributed to the study include Igor Klem, Dipan Shah, Michele Parker, Anna Lisa Crowley, Robert Judd and senior author Raymond J. Kim. Additional co-authors include Edwin Wu, Sheridan Meyers and Robert Bonow, from the Feinberg Cardiovascular Research Institute at Northwestern University.

Drs. Judd and Raymond Kim are named on a U.S. patent for DE-CMR technology, which is owned by Northwestern University. Raymond Kim and Han Kim are not related.

Michelle Gailiun | EurekAlert!
Further information:
http://www.duke.edu

More articles from Medical Engineering:

nachricht Visualizing gene expression with MRI
23.12.2016 | California Institute of Technology

nachricht Illuminating cancer: Researchers invent a pH threshold sensor to improve cancer surgery
21.12.2016 | UT Southwestern Medical Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>