Atrial fibrillation: Mending broken hearts

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Atrial fibrillation is an irregular heartbeat that can lead to blood clots, stroke and heart failure. The American Heart Association says at least 2.7 million Americans are living with the condition, which occurs when the upper chambers of the heart experience chaotic electrical signals.

But a husband-and-wife team is working to mend broken hearts.

Rolf Bodmer and his wife, Karen Ocorr, spend their days and sometimes their nights looking for the genetic mechanism that causes atrial fibrillation.

"We sometimes bring our work home in the sense that even at the dinner table, we will discuss some issues – you know, can this be, can this not be," Bodmer said.

Aging, diet, high blood pressure, even previous heart surgery can lead to atrial fibrillation.

They may find the genetic cause in fruit flies. Flies' genes are easy to manipulate, and flies age quickly, so results come in months, not years.

"We're trying to understand the genetic basis for why atrial fibrillation happens, and if we understand that genetic basis, we have a chance to identify targets we can use to develop drugs and therapies," Ocorr said.

Donna Marie Robinson is watching atrial fibrillaation research advance closely. Three years ago, she thought she was fit and healthy, then she collapsed. The diagnosis: atrial fibrillation, ventricular tachycardia, heart failure and more.

She has had to curb her active lifestyle.

"I would want to be with my friends in the spinning room, and I can't," Robinson said. "My defibrillator would probably shock me off the bike."

She's hopeful a cure is close.

Ocorr believes they'll find a genetic network for atrial fibrillation. Then, they can start testing therapeutics both on fruit flies and on human tissue.

They're already getting atrial fibrillation patient tissue samples from cardiologists around the world for further testing.

REPORT #2658

BACKGROUND: Atrial fibrillation, also known as AFib, is an irregular heartbeat (arrhythmia) that can lead to various heart-related complications such as blood clots, stroke, and heart failure. The normal contraction of the muscle fibers of the upper chambers of the heart (the atria) typically allow for the coordinated and complete emptying of blood from the heart's upper chambers into its lower ones (the ventricles). Blood that's not completely pumped out of the atria can remain and may pool there. To maximize the efficiency of the heart and to avoid various diseases, the upper and lower chambers of the heart should work as a team. That doesn't happen during AFib. It is estimated that about 2.7 million to 6.1 million people in the U.S. have AFib. That number is projected to rise to 12.1 million in 2030. The worldwide estimated number of individuals with AFib in 2010 was 33.5 million. In the U.S., 2% of people younger than 65 years old have AFib and 9% of people ages 65 and older have AFib. (Source:

SYMPTOMS AND COMPLICATIONS: Symptoms of AFib are not always felt. Some common symptoms include heart palpitations and shortness of breath. Other symptoms are irregular heartbeat, lightheadedness or dizziness, faintness or confusion, extreme fatigue, or chest discomfort and pain. There's increasing awareness that AFib is frequently unrecognized but a serious condition. Whether you have symptoms or not, AFib puts you at greater risk for stroke. According to the American Heart Association, if you have AFib, you're 5 times more likely to have a stroke than someone who doesn't have it. If your heart beats too fast, it could lead to heart failure. AFib can cause blood to clot in your heart. These clots can travel in the bloodstream, eventually causing a blockage. Research has shown that women with AFib are at greater risk of stroke and of dying than men with AFib. (Source:

GENETICS AND ATRIAL FIBRILLATION: Reports of familial clustering of AFib date back to the early 1940s. Familial AFib was generally regarded as a rare condition for many years. Over the past decade a major paradigm shift occurred with widespread recognition of the heritability underlying AFib. In the community-based Framingham Heart Study, 27% of individuals with AFib had a first-degree relative with AFib confirmed by electrocardiography. Familial AFib was associated with a 40% increased risk of AFib for another family member over a subsequent 8-year period. The risk associated with familial AFib remained even after adjustment for established clinical risk factors. A study from Denmark demonstrated that AFib was more common among monozygotic twins as compared with dizygotic twins, implicating a genetic predisposition to the arrhythmia even among those raised with shared environmental exposures. In numerous reports, the heritability of AFib appears to be greatest among younger individuals and those without structural heart disease. Premature familial AFib, or that occurring in family members 65 years of age or younger, was associated with a 2-fold increase in the risk of AFib compared with individuals without familial AFib in the Framingham Heart Study. (Source: