Millions of people have a heart rhythm disorder called atrial fibrillation, which causes the heart’s upper chambers or atria to beat chaotically rather than in a smooth, coordinated rhythm. For many, the symptoms can be mild with palpitations, fatigue or breathlessness, but the greatest danger is something far more serious – a stroke.

Tucked inside the heart is a tiny pouch called the left atrial appendage. When the heart beats erratically, blood can pool and sit still in this pouch instead of flowing normally – and still blood tends to clot. If one of those clots breaks free and travels to the brain, it can block bloodflow and cause a stroke. Atrial fibrillation makes you about five times more likely to have a stroke. The question for researchers, then, has been whether that pouch could simply be taken out of the equation.

Researchers recently revealed one possible answer – a new technique, so far tested only in animals, in which a magnetically guided liquid is injected into the heart, hardening to permanently seal the pouch from the inside. Early tests in rats and pigs suggest that this method could one day lower the risk of stroke in people with atrial fibrillation.

Current treatments are effective but imperfect. Today, most patients are prescribed blood-thinning drugs, such as anticoagulants. These drugs reduce the ability of blood to clot and significantly lower the risk of having a stroke.

However,........

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