When the heart keeps finding its own beat
Catheter ablation is one of cardiology's most impressive procedures.
A doctor threads a thin tube into the heart and zaps tiny areas causing abnormal rhythms. For many people with atrial fibrillation (AFib), it's a powerful reset button.
But for those with nonparoxysmal AFib — the more stubborn, longer-lasting form — the reset often doesn't stick. The irregular rhythm comes back, and patients go through ablation again, sometimes more than once.
AFib is the most common sustained heart rhythm problem.
It raises stroke risk, worsens heart failure, and chips away at quality of life. Paroxysmal AFib (episodes that come and go) usually responds well to ablation. Nonparoxysmal AFib, which lasts more than a week at a time, is much harder to control.
Doctors have been searching for ways to boost ablation's staying power — especially in patients with high blood pressure, which is a common driver of AFib.
The old way vs. a new idea
Normally, after ablation, patients continue their usual blood pressure medications — often ACE inhibitors or ARBs.
The new idea in this trial was to swap that standard drug for sacubitril/valsartan, better known by the brand name Entresto. It's already widely used to treat heart failure.
The thought: if it can calm a stressed, stretched heart in heart failure, maybe it can also help heart tissue recover and stay in rhythm after ablation.
How it works, in simple terms
Think of the atrium — the upper heart chamber — as a drum head.
When it's stretched too thin by high pressure or chronic AFib, it becomes jittery and prone to misfiring. Ablation burns or freezes the rogue electrical spots, but a stretched drum head tends to develop new ones.
Sacubitril/valsartan works through two pathways. It blocks one stress signal (like valsartan alone) and boosts helpful hormones that relax and protect heart tissue. The combo may help the atrium shrink back toward normal and stay less excitable.
The study at a glance
The FUNCTION Study was a randomized clinical trial of 240 nonparoxysmal AFib patients with high blood pressure.
After radiofrequency catheter ablation (RFCA), participants were split into two groups: one received sacubitril/valsartan (the ARNI group), the other continued standard care.
The primary outcome: being free of AFib or related rhythm problems for at least 30 seconds without antiarrhythmic drugs at 15 months, after the standard 3-month post-ablation "blanking period."
At 15 months, about 80% of the sacubitril/valsartan group stayed in normal rhythm, compared to about 69% of the control group.
That's roughly a 10-percentage-point absolute improvement. The hazard ratio suggested about 40% lower risk of recurrence in the treated group.
The ARNI group also saw a smaller left atrial diameter and lower NT-proBNP (a heart stress marker) than controls.
This means the pill appeared to help the atrium physically shrink and behave better, not just delay a relapse.
The biggest benefits were seen in a specific subgroup: patients with weaker pumping (ejection fraction below 50%) or areas of scarred atrial tissue. In those patients, the ARNI group had dramatically higher success rates.
A twist in the results
Interestingly, when rhythm problems did come back, they looked different between groups.
Patients in the ARNI group had fewer recurrences of AFib itself but more episodes of atrial tachycardia or atrial flutter — related but distinct rhythm problems.
This is an unusual pattern that will need more study. It might reflect how the drug reshapes the atrial tissue — preventing the chaotic AFib pattern but leaving room for more organized abnormal rhythms.
This is an interesting pivot for a drug originally designed for heart failure.
If the finding holds up in larger trials, sacubitril/valsartan could earn a new role in cardiology: helping ablation work better for the hardest-to-treat AFib patients, especially those with weakened heart function or atrial scarring.
It also fits a broader trend of extending heart failure therapies into related heart conditions.
If you've had an ablation for persistent AFib and you also have high blood pressure — especially with weakened heart function — it may be worth discussing sacubitril/valsartan with your cardiologist.
This isn't a DIY decision. The drug requires careful dosing, can lower blood pressure too much, and may interact with other medications.
If your AFib is the paroxysmal type or your heart function is completely normal, this particular benefit may not apply directly to you.
Honest limitations
This was a single-trial result with 240 patients at what appears to be a limited number of centers.
Findings will need confirmation in larger, multi-center, international trials before they change guidelines. The 15-month follow-up is medium-length; longer-term durability is unknown. The higher rate of atrial flutter/tachycardia in the ARNI group also deserves careful evaluation.
Larger trials will likely explore whether sacubitril/valsartan helps across broader populations — including patients without hypertension or with different AFib types.
Researchers will also want to know whether starting the drug before ablation offers even greater benefit, and how long treatment should continue afterward.
For now, the FUNCTION Study opens an intriguing door: a familiar heart failure drug may also help some of the hardest hearts to keep in rhythm.