- A new European study of pulsed-field ablation has found that men and women receive similar positive results from this new treatment for atrial fibrillation.
- Pulsed-field ablation uses rapid-fire electrical pulses to deaden tissue in pulmonary veins that over-excite the left upper atrium of the heart, causing atrial fibrillation.
- Unlike currently used thermal ablation procedures, pulse field ablation can be tightly targeted, eliminating unwanted damage to nearby tissue.
Researchers are reporting promising results for a new treatment for atrial fibrillation (AFib) called pulsed field ablation.
In their new study published in the journal JAMA Cardiology, researchers cast doubt on previous research that reported inconsistencies in outcomes for men and women treated for AFib using conventional thermal ablation treatments such as radio-frequency ablation and cryoablation.
Researchers report that at the one-year mark, both sexes were free of AFib after treatment with pulsed field ablation.
The study reports the results of pulsed field ablation post-regulatory approval treatments between March 2021 and May 2022 under the auspices of MANIFEST-PF, a multinational post-regulatory approval program conducted at 24 European clinics.
The program involved 1,568 participants. Men who received pulsed field ablation were an average of 62 years old. Women in the program had an average of 68 years, although they had fewer co-morbidities.
Additional ablation was performed on 22% of the women and 23% of the men.
At the one-year mark after the procedure, researchers reported that 79% of men and 76% of women had no signs of AFib, a difference the authors consider insignificant.
Atrial fibrillation and what causes it
AFib is a condition in which the heartbeat is irregular. It is a type of arrhythmia.
AFib can result in serious outcomes such as strokes and blood clots as well as heart failure.
The condition occurs in the left upper chamber, or atrium, of the heart. With AFib, the atrium fails to successfully pump out all the blood that enters it from the lungs, resulting in pools of blood remaining in the chamber.
Within these pools, clots can form. These clots may eventually exit the heart, reaching the brain and causing a stroke.
“The theory is that there is a trigger that starts [the atrium] beating really fast,” said Dr. Paul Drury, a Southern California cardiologist who was not involved in the study. “So when we do an ablation for atrial fibrillation, we are trying to eliminate the trigger for the AFib.”
“It’s very hard to pinpoint where it’s coming from because when we’re in there, it looks like chaos, so to speak,” Drury added.
What doctors have found is that, for the vast majority of people with AFib, the trigger is the pulmonary veins connected to the atrium, Drury explained.
These veins are electrically active and ablation attempts to block the electrical signal coming into the atrium by deadening cells in the veins.
“Those in the pulmonary veins just are — we don’t know why — more electrically active” in people with AFib, Drury told Medical News Today.
Left untreated, the upper-left atrium of a person with AFib can beat 300 to 400 times a minute.
This results in shallow, unproductive pulses that fail to adequately grab and clear blood from the chamber.
For many people, there are no perceptible symptoms of AFib, although others may experience a noticeably rapid, pounding heartbeat, accompanied by light-headedness and a shortness of breath.
Between 2 million and 6 million people in the United States are estimated have AFib. That number is expected to rise as the U.S. population grows older to 12 million people by 2030.
Pulsed-field ablation for AFib
To treat AFib, cardiologists use a method called “ablation.”
“The goal,” explained Dr. Jayne Morgan, a cardiologist in Atlanta who was not involved in the study, “is to restore normal sinus rhythm by disrupting aberrant electrical pathways in the heart.”
“The goal is also to restore and/or improve the quality of life by reducing or eliminating the often disturbing symptoms of palpitations, and sometimes fatigue, lightheadedness or even shortness of breath,” she told Medical News Today.
The most frequently employed forms of ablation are thermal. Radio-frequency ablation burns tissue around the pulmonary veins with heat to kill cells, protecting the atrium from the excessive electrical charge. Cryoablation does the same thing, using cold to freeze cells.
Either of these methods may cause problems, however.
“When you do radio-frequency or cryo,” said Drury, “if you’re ablating the heart, you can also ablate the esophagus. You can also ablate the phrenic nerve.”
Pulsed field ablation, on the other hand, he said, uses “an electrical pulse which actually punches little holes in the cells, and it causes them to die that way. It punches holes in the cell membrane with very quick, high-amplitude, high-energy pulses of electricity.”
Experts say a significant advantage of pulsed field ablation is that it can be tuned for the desired type of cell, avoiding collateral damage so frequently experienced with thermal ablation. It is also much quicker than thermal ablation, which requires minutes, as opposed to seconds.
Drury lauded early trial results of pulsed field ablation, saying “the preliminary studies show great safety data and great efficacy.” Still, with any new procedure such as this, “since it is a newer technology, it will inevitably have some growing pains. There always are.”
He called pulsed field ablation “very, very promising.” The procedure is not yet approved in the United States.
Men and women achieving the same results
The authors of the paper reported that with pulsed field ablation, men and women experienced similarly positive outcomes.
It may be, however, that the difference does not lie in the use of pulsed field ablation. Drury suggested one reason is that irregularities in other studies have clouded an assessment of ablation results for men and women.
“A number of reasons,” said Morgan, “have been postulated for this difference, including, a general greater advanced age in women at the time of procedure in comparison to men, which also then contributes to a higher number of co-morbidities at the time of procedures.”
Morgan noted that “women have often suffered with symptoms for a longer period of time before presenting to the medical establishment.”
“Once seen by a medical professional,” she added, “women often have further delays or even less frequent referrals for catheter ablations, creating a longer duration of AFib at the time of the procedure.”
Drury proposed an additional possible factor. He noted that most studies focus on pulmonary vein ablation. “That is the culprit of AFib in the majority of people. I’d say 85 percent and above.”
However, for some people, AFib is the result of non-pulmonary vein triggers and women are over-represented in this group.
“I think this is why women don’t always do quite as well or do about the same [in other studies], even though they’re healthier, because we’re missing the non-pulmonary vein triggers,” Drury said.
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