Hi, my name is Dr. Salmo Oza. I'm a cardiac electrophysiologist at Ascension St. Vincent's Cardiology in Jacksonville, Florida. The topic for this talk is hybrid epicardial endocardial ablation for patients with atrial fibrillation and heart failure. Here are my disclosures. The overall topic involves atrial fibrillation and heart failure and the restoration of normal sinus rhythm. The prevalence of atrial fibrillation increases with the severity of heart failure. In fact, as the severity of heart failure increases, the persistence of the atrial fibrillation also increases. The development of atrial fibrillation in heart failure patients is one of the leading causes of clinical deterioration. Restoration to normal sinus rhythm matters, and it results in an improved ejection fraction, decrease in all-cause mortality, reduced LA dimensions, and decreased hospitalizations. The chart to my right shows the physiologic effects of atrial fibrillation over time as it becomes more and more prevalent. Initially, it starts off with atrial remodeling, such as decreased left atrial compliance, decreased left atrial reservoir function, and decreased left atrial contractility. As the burden of AFib increases, you see more global effects of the atrial fibrillation even on the ventricles, with decreased biventricular systolic function, decreased cardiac output reserve, et cetera. Those left untreated for atrial fibrillation have three to five times greater risk of stroke and an increased risk for developing heart failure. This is reflected in the new 2023 practice guidelines, which tells us to treat patients early, focus on maintaining sinus rhythm, and reducing atrial fibrillation burden. Catheter ablation now has a class one indication as first-line therapy in patients where randomized studies demonstrate superiority over drug therapy alone for rhythm control. Furthermore, catheter ablation for appropriate patients with atrial fibrillation and heart failure with reduced ejection fraction also received a class one indication. In appropriate patients with AFib and heart failure with reduced ejection fraction who are on GDMT and with reasonable expectation for procedural benefit, catheter ablation has been shown to improve symptoms, quality of life, ventricular function, as well as hard cardiovascular outcomes. This is reflected from a growing body of evidence for catheter ablation in patients with AFib and heart failure. The CAMERA MRI trial was the first of these, which looked at catheter ablation versus medical rate control and showed a significant increase in ejection fraction in the patients treated with catheter ablation. The CASEL-AF trial was the next landmark trial that was released, and it showed that catheter ablation when compared to medical therapy for rhythm control dramatically reduced by a factor of approximately 38% death or hospitalization for worsening heart failure. The CASEL heart transplant trial showed in an even sicker population of patients referred for heart transplant that the catheter ablation group had significantly less death, less implantation of LVAD, or less heart transplantation when compared to the medical therapy group, to the tune of a 76% reduction. This really shows that catheter ablation is superior in heart failure patients to medical therapy. The majority of this is really seen due to the superiority of catheter ablation to medical therapy when it comes to maintaining sinus rhythm, so it's much better at keeping people in sinus rhythm. There may be some other effects of catheter ablation that have yet to be discerned, but that's really the underlying reason why it's better for these heart failure patients. However, when we look at endocardial catheter ablation in several trials, regardless of energy source, it has limited effectiveness in patients with non-paroxysmal atrial fibrillation. So when we look at the CAPLA trial, which is one of these randomized trials, when we compare patients that had PVI only to PVI with posterior wall isolation and endocardial ablation, we saw no benefit to the addition of posterior wall isolation when it comes to freedom from atrial arrhythmias. When we look at the newest energy source, which is pulsed field ablation, we can look at the PULSED-AF trial, which was not randomized, but looked at patients in part of the trial that were persistent, and they included posterior wall isolation, and they saw an efficacy of about 55%, which is really in line with most of the trials for PVI alone in a persistent atrial fibrillation population. More recently, data was released in the MANIFEST-PF registry sub-study, and they looked at patients retrospectively with persistent atrial fibrillation who had PVI versus patients who had PVI with the left posterior wall ablated, and they showed no difference in outcomes in the MANIFEST registry. And this is a large number of over 1,500 patients that had ablations in that registry. So really, unfortunately, regardless of the energy source, we had a lot of hope for PFA that this is going to be the new therapy. I think in its current iteration, ablating the posterior wall so far hasn't really shown a whole lot of benefit. So what are we left with here? Well, when we look at paroxysmal AFib, radiofrequency ablation, cryo-balloon catheter ablation, and pulse field ablation have really shown to be very, very effective at treating early-stage atrial fibrillation, paroxysmal atrial fibrillation, and perhaps early-stage persistent atrial fibrillation. But when we move to later-stage persistent atrial fibrillation and long-standing persistent atrial fibrillation lasting longer than one year, it really hasn't done the job. And we've had to look at other novel therapies, like hybrid AFib ablation therapies, which have shown to be much more beneficial in this long-standing persistent population. And the catheters we use for the CONVERGENT procedure, which is one of the techniques that we'll talk about, are the EpiSense catheter and the steerable EpiSense ST catheters. So what is hybrid ablation? Hybrid epicardial-endocardial ablation was developed to comprehensively address the advanced AF substrate. So there's two types, the transthoracic or the TT hybrid ablation, where the cardiac surgeon epicardially, via transthoracic approaches, is able to isolate the pulmonary veins and the posterior wall with a roof and floor line, as well as eliminate the left atrial appendage, generally with an atrial clip. The other approach is the CONVERGENT hybrid procedure, in which the cardiac surgeon uses a transdiaphragmatic or subxiphoid approach to access the posterior wall of the left atrium and ablate the posterior wall using an EpiSense or an EpiSense ST catheter, as well as around the anterior aspects of the right and left pulmonary veins. And then either at the same time, in the same setting, or as a staged procedure, the electrophysiologist can go in and complete the PVI, complete the roof line if needed, as well as a right atrial flutter line, and that consists of a complete CONVERGENT procedure. Many people nowadays also, especially in the staged situation, add a left atrial appendage isolation with an atrial clip as well in this scenario. The thoracoscopic approach also permits for this left atrial appendage exclusion. Three randomized trials, one single-arm trial, and numerous observational studies have reported on the outcomes of both of these hybrid ablation techniques. So the CONVERGE trial in the upper left-hand corner compared the CONVERGENT procedure to a catheter ablation arm and showed significant improvement in the CONVERGENT arm. So this was one of the first trials that showed benefits in a randomized trial, in a large multi-center randomized trial, of anything that is better than pulmonary vein isolation alone. The CEASE-AF trial looked at a similar population of persistent and long-standing persistent AFib patients, but it used the T-Tiers, a transthoracic approach, as well as endocardial ablation, and compared it to an endocardial ablation-only group and showed significant superiority. HEART-CAP-AF was also a similar transthoracic approach, and they compared it to catheter ablation and again showed superiority when you use this combined approach compared to the endocardial ablation alone. And the DEEP trial was a non-randomized trial of long-standing persistent patients that showed a similar efficacy of around 70% in that same long-standing persistent population when you used the transthoracic hybrid approach. So hybrid AF ablation is really the only strategy that has consistently treated these very advanced forms of atrial fibrillation, and these are forms of atrial fibrillation that are quite advanced, and when you see them in your clinic, you're really kind of scratching your head as to how to treat these patients. So in the entire population of atrial fibrillation, this is a good approach in those most advanced patients. Now let's move to patients with a left ventricular and left atrial size pre- and post-hybrid transthoracic ablation for AFib. So this is a single-site retrospective trial that looked at about 40 patients with long-standing persistent and persistent atrial fibrillation with reduced ejection fractions. This is that heart failure population. They had tachycardia-mediated cardiomyopathy and heart failure. The pre-op AF duration, so the time that they were in persistent atrial fibrillation with no sinus rhythm, was about five and a half years. So that's a very advanced population. They had an ejection fraction of less than 40% and a New York Heart Association class of two or worse. They underwent the hybrid transthoracic ablation and basically had results that looked quite promising in this population. The EF improved significantly by 12%. The mean left atrial size decreased. The New York Heart Association class improved significantly. Rhythm success was achieved in greater than 60% of patients during a mean of three and a half years follow-up. So that's quite a long follow-up in these patients as well. So they showed very promising results in that long-standing persistent patient with heart failure. So we actually looked at this population as well with several other centers. We had a retrospective trial that included 158 patients that were treated with the convergent procedure. So this wasn't the transthoracic procedure, but the convergent procedure. 98% had persistent atrial fibrillation and long-standing persistent atrial fibrillation. 44% of these patients had a low ejection fraction, less than 55%. So that's the group that we really looked at. That group had a mean pre-op AF duration of nearly six and a half years. 27% had failed previous endocardial ablation. We looked at 2D echocardiography to measure the ejection fractions after the ablation. Because this was a retrospective trial, we didn't have rhythm data on all these patients. We had rhythm data on about 73% of those patients. And in that group that we could look at, we had approximately a 60% success rate when it came to freedom from atrial fibrillation. So reasonable in that long-standing persistent population. When we looked at our outcomes, we saw that with that 60% success rate, we still had a significant improvement in ejection fraction in all of those patients that had an EF of less than 55%. When we looked at the severely reduced ejection fractions, we still saw a significant increase as well as the moderate group. And then the entire cohort of all those patients were kind of boosted by the improvement that we saw in the low EF patients. So overall, they even had a significant improvement in ejection fraction when you looked at the entire cohort. When you look at the improvements, the improvements were greatest in the, I'm sorry, when you look at the success rate of the procedure, the success rate was greatest in the patients that had the highest ejection fraction. So as the ejection fraction gets lower and lower, the success rates decrease with the procedure. However, we still saw a significant improvement in even those very sick patients with EFs of less than 40%. So in summary, difficult to treat patients with a persistent and longstanding persistent atrial fibrillation with reduced LVEF showed significant improvement in left ventricular function following the hybrid convergent ablation. These data add to the growing body of evidence that hybrid ablation positively impacts the ejection fraction. So our key takeaways from this talk. Number one, the latest guidelines recommend catheter ablation as a class one indication in appropriate patients with atrial fibrillation and heart failure with reduced ejection fraction. Number two, longstanding persistent atrial fibrillation is the largest population of patients with atrial fibrillation. So we really have to find a way to treat these patients with longstanding persistent EF, because that's the largest group of patients that need our help. Endocardial catheter ablation alone is limited in its effectiveness to restore and maintain sinus rhythm in patients with advanced EF or longstanding persistent atrial fibrillation. Hybrid ablation is a superior strategy over endocardial ablation alone to treat advanced atrial fibrillation and achieve sinus rhythm. Recent trials demonstrate improvements in injection fraction and lower occurrence of AF in patients with advanced EF. Improvements in injection fraction and lower occurrence of AF amongst heart failure with reduced ejection fraction patients who underwent catheter ablation. Emerging evidence suggests that hybrid ablation improves ejection fraction in patients with AFib and heart failure with reduced ejection fraction. However, randomized trials are going to be needed to further validate these findings. So hopefully that'll be coming soon. Well, that concludes my talk. I hope this was helpful and everybody learned something from these points that I have made. I appreciate your listening. Thank you.

hybrid ablation

atrial fibrillation

heart failure

cardiac electrophysiologist

catheter ablation