Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sleep disorder linked to common, serious heart rhythm problem

27.05.2003


A heart rhythm disturbance that affects more than 2 million Americans is twice as likely to recur in patients with untreated sleep apnea, according to a Mayo Clinic study published in the May 27 edition of Circulation: Journal of the American Heart Association. Obstructive sleep apnea (OSA) is a condition that causes people to repeatedly stop breathing during sleep.



Atrial fibrillation (AF) is the most common sustained heart arrhythmia and can have serious consequences. When the upper chambers of the heart quiver rapidly and erratically -- as many as 400 times per minute -- blood does not move efficiently through the heart. This pooling blood is more likely to clot, leading to heart attacks or strokes. AF also can lead to heart failure by causing the heart’s main pumping chambers, the ventricles, to contract rapidly -- often more than 100 beats per minute.

AF treatment involves using electrified paddles on the chest to shock the heart back into the proper rhythm, a procedure called cardioversion. Medications can help maintain normal rhythms, but lasting results are difficult to achieve; more than half of patients fall back into AF within one year.


In the Mayo Clinic study, OSA was the single factor most closely associated with recurrence of AF.

"Other recent studies have suggested that AF may be more common in patients with sleep apnea," says Virend Somers, M.D., Ph.D., the Mayo Clinic cardiologist who led the study. "To our knowledge this is the first study showing that untreated OSA is associated with an increased risk of recurrent atrial fibrillation, and that the risk is not explained by other conditions but rather appears to be due to the presence of untreated OSA itself."

Dr. Somers likens OSA to the collapse of a soda straw that has one end blocked. "In OSA, the upper part of the airway essentially collapses when people inhale during sleep. To overcome the obstruction, the patient breathes in harder, which generates very high negative pressures that can make the collapse worse," he explains. "This raises blood pressure, lowers blood oxygen levels and stretches the walls of the atria, making them susceptible to irregular electrical rhythms." One of several treatments for OSA is wearing a continuous positive airway pressure (CPAP) device while sleeping. CPAP uses tubes to apply air through the nose and mouth, which overcomes the collapse.

Dr. Somers’ group compared 43 AF patients who had been diagnosed with OSA with 79 controls who were also treated at the Mayo Clinic Cardioversion Center but had not been diagnosed with the sleep disorder. The researchers were able to follow 39 of the OSA patients, 27 of whom either got no OSA treatment or used it inappropriately (less than five times per week) for a year after cardioversion. AF recurred in 82 percent of the patients with untreated OSA, compared to 42 percent in the treated OSA group. The controls had a 53-percent recurrence rate.

The study results are particularly important because the prevalence of OSA increases with obesity, which is an American epidemic. "It is conceivable that a consequent increase in obstructive sleep apnea may contribute to the dramatic increase in the incidence of AF, which has nearly tripled during the past three decades," Dr. Somers says.

"In the general population, the estimated prevalence of significant OSA is 24 percent for men and 9 percent for women ages 30 to 60, and is even higher when associated with obesity or cardiovascular disease, such as high blood pressure," he explains. "Our control group had a high prevalence of obesity, so it is quite likely that many of those 79 control patients actually had undiagnosed -- and therefore untreated -- sleep apnea. Given the high prevalence of obstructive sleep apnea and the emerging epidemics of obesity and AF, our findings of an increased risk of AF in untreated OSA patients may have implications for both diseases."

Dr. Somers suggests that selected patients with AF should be screened for OSA because successful treatment may reduce the risk for this heart rhythm disturbance. Leading candidates are those with recurrent AF who are obese, whose spouses say they snore loudly or who have seen them stop breathing, or who experience daytime sleepiness.

The lead author of the paper is Ravi Kanagala, M.D. Co-authors are Narayana Murali, M.D.; Paul Friedman, M.D.; Naser Ammash, M.D.; Bernard Gersh, M.B., Ch.B.; Karla Ballman, Ph.D.; and Abu Shamsuzzaman, M.D., Ph.D.

Lee Aase | EurekAlert!
Further information:
http://www.mayo.edu/

More articles from Health and Medicine:

nachricht New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University

nachricht Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine

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: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

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....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>