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 reports about: > DE-CMR > ECG > Medical Wellness > Non-Q-wave attacks > Q-wave > UMIS > artery disease > blood enzyme levels > coronary artery disease > damaged tissue > electrocardiograms > heart attacks > imaging technology > myocardial infarction > non-Q-wave myocardial infarctions > silent heart attacks > unrecognized myocardial infarctions
First transcatheter implant for diastolic heart failure successful
16.11.2017 | The Ohio State University Wexner Medical Center
Theranostic nanoparticles for tracking and monitoring disease state
13.11.2017 | SLAS (Society for Laboratory Automation and Screening)
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences