Millions of people experience a heart rhythm disorder called atrial fibrillation, which makes the heart’s upper chambers, or atria, beat irregularly instead of in a steady, coordinated pattern.
For some, symptoms are mild, including palpitations, fatigue, or shortness of breath. However, the most serious risk is a stroke.
Inside the heart lies a small pouch known as the left atrial appendage. When the heart beats unpredictably, blood can collect and stagnate in this pouch rather than flowing normally — and stagnant blood is prone to clotting.
If a clot dislodges and travels to the brain, it can block blood flow and trigger a stroke.
Atrial fibrillation increases the risk of stroke by roughly fivefold. This has led researchers to ask whether the left atrial appendage could be effectively “removed” from the equation.
Magnetically Guided Liquid Seals Heart Pouch in Animal Tests
A recent study offers a potential solution: a new technique, tested so far only in animals, where a magnetically guided liquid is injected into the heart and hardens to permanently seal the pouch from within.
Preliminary experiments in rats and pigs indicate that this approach could one day reduce stroke risk in people with atrial fibrillation.
Current treatments work but aren’t flawless. Doctors prescribe most patients blood-thinning medications, such as anticoagulants, to reduce clotting and significantly lower stroke risk.
Yet, these drugs carry risks. They raise the chance of bleeding, which can be dangerous—especially for older adults or those with conditions such as stomach ulcers, high blood pressure, liver or kidney disease, or cancer. Some patients cannot tolerate anticoagulants or must stop taking them due to bleeding complications.
Doctors can also perform left atrial appendage occlusion, implanting a small device to block the appendage. Doctors deliver the most common devices through a catheter, where they expand like a tiny metal umbrella to seal the opening.
While effective, these devices aren’t perfect. The appendage varies greatly in shape and size between individuals, so rigid implants may not always form a complete seal. Blood can sometimes leak around the edges, clots may form on the device’s surface, and the anchoring parts can potentially damage heart tissue.
A Flexible Heart Solution
The newly developed method follows a completely different approach. Rather than placing a rigid device, researchers inject a magnetically responsive liquid—often called a magnetofluid—directly into the left atrial appendage using a catheter.
Once inside, an external magnetic field guides and stabilizes the fluid, allowing it to completely fill the appendage, even against the flow of blood.
Within minutes, the liquid interacts with blood, solidifying into a soft “magnetogel” that effectively seals the cavity.
Since the material starts as a liquid, it can conform perfectly to the uniquely irregular shape of each patient’s left atrial appendage.
In theory, this enables a more complete seal compared with traditional rigid devices.
The gel also seems to merge with the heart’s inner lining, creating a smooth surface that could lower the risk of clot formation.
Promising Initial Findings
So far, the technique has only been tested in animals. Researchers first evaluated the concept in rats and then progressed to experiments in pigs, an important milestone in cardiovascular research.
In the pig study, the magnetogel remained stable inside the appendage for 10 months with no evidence of a clot or leakage.
The heart’s inner lining grew over the gel’s surface, forming a continuous, seemingly healthy layer.
Compared with traditional metal occlusion devices in pigs, the magnetogel created a smoother lining and avoided the tissue damage caused by anchoring barbs. Importantly, the researchers observed no harmful biological effects in the animals.
Pigs are commonly used in cardiovascular studies because their hearts closely resemble human hearts in size, structure, and function.
Pig Studies Show Promise, Human Safety Unclear
Demonstrating that the magnetofluid works safely in a pig heart offers an important proof-of-concept, but it does not yet guarantee that the technology will be safe or effective in humans.
Although the results are encouraging, the technique is still in the experimental phase. Before human trials can start, researchers need to confirm long-term safety, refine the delivery method, and verify that the material behaves consistently in larger animal studies.
There are also practical challenges to address. For instance, the magnetic material can interfere with MRI heart scans, making certain areas harder to image.
Issues like these must be resolved before patient use, and medical devices require extensive testing, meaning it could be many years before the technique becomes a clinical treatment.
If proven safe and effective in humans, this approach could offer a new way to protect people with atrial fibrillation from stroke. A catheter-delivered liquid seal might provide an alternative for those who cannot take anticoagulants and could overcome some of the drawbacks of current occlusion devices.
Read the original article on: Sciencealert
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