Cardiac procedure cuts risk of Alzheimer”s disease and stroke

May 14, 2010 By Leave a Comment

Washington, May 14 (ANI): Catheter ablation, treatment of the most common heart rhythm disorder, significantly reduces the risk of stroke, mortality, Alzheimer”s disease and other forms of dementia, researchers have found.

The finding, by researchers from the Heart Institute at Intermountain Medical Center in Murray, Utah, was presented at National Heart Rhythm Society Sessions.

According to two studies, patients with atrial fibrillation treated with catheter ablation are less likely to develop Alzheimer”s disease or other forms of dementia, and have a significantly reduced risk of stroke and death compared to A-fib patients with who are not treated with ablation.

During atrial fibrillation, the heart”s two small upper chambers quiver instead of beating effectively.

Blood isn”t pumped completely out of them, so it may pool and clot. If a piece of a blood clot in the atria leaves the heart and becomes lodged in an artery in the brain, a stroke results. (ANI)

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Sleep-related breathing disorders linked to irregular heartbeats

June 23, 2009 By Leave a Comment

Washington, June 23 (ANI): A new study led by an Indian origin scientist has revealed that sleep-related breathing disorders can lead to serious cardiovascular problems in older adults.

Dr Reena Mehra, of Case Western Reserve University School of Medicine, Cleveland has found a link between apnea (brief pauses in breathing) or hypopnea (shallow breathing) and abnormal heart rhythms (arrhythmias) in older men.

The study involving 2,911 men showed that having more episodes of paused or shallow breathing was associated with increased odds of two types of arrhythmias-one involving the heart’s upper chambers (atria) and one involving the heart’s lower chambers (ventricles).

Obstructive sleep apnea-the most common type, involving a partial or complete blockage of the airways-was associated with irregular heartbeats caused by a problem with the lower chambers or ventricles.

In addition, lower blood oxygen levels also appeared to be associated with this type of arrhythmia.

But central sleep apnea, involving a malfunction in brain signals controlling breathing muscles, was more strongly associated with arrhythmias in the atria or upper chambers.

According to the authors, more severe cases of sleep-disordered breathing were associated with higher odds of arrhythmia; in addition, “there also seems to be a threshold effect such that moderate-to-severe sleep-disordered breathing confers the greatest increased odds of clinically significant arrhythmias independent of self-reported heart failure and cardiovascular disease.”

“The strong associations between central sleep apnea and atrial fibrillation [arrhythmia originating in the heart's upper chambers] suggest that central sleep apnea may be a sensitive marker of underlying abnormalities in autonomic or cardiac dysfunction associated with atrial fibrillation,” they added.

The study appears in Archives of Internal Medicine, one of the JAMA/Archives journals. (ANI)

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Chickens could help provide solutions for human heart abnormalities

January 22, 2009 By Leave a Comment

Washington, Jan 22 (ANI): By focussing on chickens’ hearts, a scientist at University of Missouri has identified some proteins in the heart muscle that are critical in regulating embryonic heartbeat control.

Knowledge of these components and how they interact can enable researchers with a better understanding of heart development and abnormalities in humans.

For the study, the researchers examined embryonic chickens’ hearts, which develop morphologically and functionally similarly to humans’ hearts.

They then tested the electrical activity present in the cardiac muscle cells over a period of 24 hours, and found that the changes in local proteins have important effects on embryonic heart beat control.

“Electrical activity in the heart appears in very early stages of development. This study determined the role of the heart microenvironment in regulating electrical activity in cardiac cells that are required for normal cardiac function,” said Luis Polo-Parada, assistant professor in the Department of Medical Pharmacology and Physiology in the MU School of Medicine and investigator in the Dalton Cardiovascular Research Center.

He added: ” Understanding exactly how a heart is made and how it begins to function will allow us to significantly improve therapies for a wide range of cardiac anomalies, injuries and diseases such as hypertension, cardiac fibrosis, cardiac hypertrophy and congestive heart failure.”

Cardiac function depends on appropriate timing of contraction in various regions of the heart.

The electrical signals that arise within the heart cells that initiate contraction of the heart muscle are essential to the control of the heart.

The upper chambers of the heart, the atria, must contract before the lower chambers, the ventricles, to obtain a coordinated contraction that will propel the blood throughout the body.

Although scientists understand the gross actions of the electrical signals that drive cardiac contraction, they still don’t have a full idea of the changes in the local environment of the embryonic and adult heart cells that influence these contractions. (ANI)

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