Atrial fibrillation (AF or AFib) is the most common type of heart arrhythmia, affecting millions of people worldwide. Researchers have now developed a new procedure that shows great promise as a safe, quick and effective alternative to existing surgical methods used to treat the condition.
In someone with AF, the heart’s top chambers (atria) beat irregularly or "flutter", so blood doesn’t flow as well as it should into the lower chambers (ventricles). AF can be a one-off, occasional, or permanent condition.
It’s important that persistent AF be treated because the irregularly beating atria are prone to develop blood clots, which can break free and circulate in the bloodstream, lodging in a blood vessel in the brain and causing a stroke. Treatment can include medication to slow or normalize the heart rhythm, blood thinners to reduce the formation of blood clots, or surgery.
Surgery, called catheter ablation, is an effective treatment for symptomatic AF that hasn’t responded to medication. A long, flexible tube is fed into the heart’s blood vessel through a vein in the leg, neck or under the clavicle. The traditional method is thermal ablation, where heat or extreme cold is applied to the tissues causing the arrhythmia, ablating (destroying) the tissue and creating scar tissue that helps prevent it from recurring.
A new international study has used electrical pulses instead to ablate the heart tissue and found that it is just as effective as thermal energy in treating AF. Moreover, it’s quicker, and there is less risk of thermal-related complications.
Called pulsed field ablation, the technique uses electrical pulses to create tiny holes in the membranes of heart muscle cells, causing the cells to die. It's previously been used to treat cancer by targeting and killing tumor cells but has only recently been considered suitable for treating arrhythmias.
The study was conducted at 41 sites in nine countries: the US, Canada, Australia, Austria, Belgium, France, Japan, the Netherlands, and Spain. Participants had AF that had not responded to drug treatment. Half of the participants had paroxysmal AF, where episodes of arrhythmia are self-terminating and don’t last more than a week, and half had persistent AF, where episodes last at least a week and don’t end on their own.
Doctors first treated one participant each to gain experience with the pulsed field ablation technique before performing an additional 300 procedures between all sites.
Of participants with paroxysmal AF, 66% experienced no episodes of AF between three and 12 months after the procedure. Of those with persistent AF, 55% had no AF episodes in the same period. These rates are consistent with outcomes achieved with thermal ablation.
There was a very low incidence of procedure-related adverse events – one in each participant group – compared to thermal ablation, which can cause damage to the heart’s valves and blood vessels.
Further, the pulsed field ablation procedure took less than one hour, which is substantially faster than the thermal method, which typically takes two or more hours to complete. All participants reported significant improvements in quality of life.
“The efficacy of the procedure is similar to what we see in thermal ablation, but we’re getting it much faster and with much more safety,” said Dr Atul Verma, the study’s lead author. “Many physicians feel that pulsed field ablation will become the dominant way of doing ablation moving forward, so in that sense, it’s really a paradigm shift.”
The researchers are mindful of the study’s limitations, particularly that no control group was used. While larger studies are needed to confirm the procedure’s safety, researchers are confident that the safety and success of pulsed field ablation will improve as technology advances.
The study was published in the journal Circulation.
Source: American College of Cardiology via EurekAlert!
