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 Biofilm discovery suggests new way to prevent dangerous infections
23.05.2017 | University of Texas at Austin

nachricht Another reason to exercise: Burning bone fat -- a key to better bone health
19.05.2017 | University of North Carolina Health Care

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: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>