Conference Takeaways

In this short interview video from HRS 2022, Dr Katrine Emilie Frimodt-Moeller (University of California San Francisco, San Francisco, CA, US) discusses the findings from a recent study which aimed to determine the effects of intensive blood pressure treatment compared to usual care in patients with incident left-ventricular conduction disease.

Discussion points:
1. Aim, study design and endpoints
2. Main findings
3. Impact on clinical practice
4. Patient eligibility
5. Take-home messages for clinicians
6. Next steps

Recorded onsite at HRS 2022, San Francisco.

Transcript:

– So my name is Emilie Frimodt-Moller. I’m a medical student from University of Copenhagen in Denmark, and is currently holding a position as a junior research specialist at University of California, San Francisco. I’m here to present or talk about this study, ‘Effect of Intensive versus Standard Blood Pressure Treatment on Incident Left-Ventricular Conduction Disease’.

Aim, study design and endpoints

Yeah, so, a little background of the study is that we know that cardiac conduction disease can lead to poor outcome, including heart failure and eventually death, but the prevention of cardiac conduction disease is still not part of cardiac care. And I think the reason for that is that we actually don’t know how to prevent it or even if we can prevent it. So right now, the way we think about conduction disease is that it’s not a modifiable outcome but more like it’s just bad luck for the patients. So previous studies, which have all been observational, they have found a common predictor of conduction disease, which is hypertension. And this is especially associated with left-ventricular conduction disease. So that is fascicular and left bundle branch block. So we thought that if hypertension can increase the risk of left-ventricular conduction disease, then maybe we can prevent the development of left-ventricular conduction disease by a more aggressive blood pressure control. So the aim of this study was to test that hypothesis, and then we were very lucky to be able to use data from the SPRINT trial, which was a two multi-center randomised clinical trial that randomised hypertensive individuals to receive either a standard blood pressure treatment for a systolic blood pressure target below 140 millimetre mercury or an intensive treatment for a systolic target below 120 millimetre mercury.

Main findings

So our endpoint was left-ventricular conduction disease which is fascicular bundle branch block and left bundle branch block. Yes, so our main findings was that the participants randomised to an intensive blood pressure control had a 26% lower risk of developing left-ventricular conduction disease. And this was very consistent across all of our analysis and also when we considered all-cause death as a competing risk. Another quite interesting finding was that the risk of right bundle branch block did not differ between the treatment groups. So that was kind of a negative control to our main findings.

Patient eligibility

Of course, we cannot generalise these findings to all patient populations. We do have some limitations with that. We didn’t look at patients who already had left-ventricular conduction disease. All of our patients, they were free of left-ventricular conduction disease at baseline but I don’t see any reasons for not to think of this patient group as being able to benefit from a more aggressive blood pressure control.

Take-home messages

I think our take-home message is that the way we see conduction disease, first of all, a take-home message is that we saw a high reduction in left-ventricular conduction disease by more aggressive blood pressure treatments, and the way we see conduction disease should not be that it’s just bad luck for the patient but that it actually is a modifiable outcome that is susceptible to prevention strategies.

Next Steps

I think there are a couple of next steps but what’s very important is to continue looking into modifiable risk factors of conduction disease, since hypertension is likely only one among other risk factors that we can actually modify and therefore try to prevent conduction disease. But it would also be very important to identify the individuals who is at highest risk of developing left-ventricular conduction disease so that we can identify the individuals who would benefit the most from a prevention strategy with least harm.

In this short interview, Dr Jeff Healey (McMaster University, Hamilton, CA) talks about the key data from the ATLAS (Avoid Transvenous Leads in Appropriate Subjects) trial (NCT02881255).
The aim of the study was to compare standard, single chamber transvenous ICD (TV-ICD) to sub-cutaneous ICD (S-ICD)(Boston Scientific EMBLEM) in occurrence of perioperative and long term device related complications and failed appropriate clinical shocks and arrhythmic death.

Discussion Points
Trial Backgound
Study Design & Eligibility Criteria
Key Findings
When to Select S-ICD Over TV-ICD
Implications for Practice & for Guidelines
Next Steps

Recorded on-site at Heart Rhythm 2022, San Francisco.

In this short interview Dr James V Freeman (Yale University School of Medicine, New Haven, CT, US) discusses the key findings from the study investigating in-hospital outcomes for Next-Generation Watchman FLX compared with Watchman Generation 2.5.

Discussion Points
Importance of this Study
Key Differences Between the Studied Devices
Study Design and Patient Baseline Characteristics
Key Findings
Correlation Between Procedure Volume and Safety Events
Take-home Messages for Clinicians
Next Steps

Recorded on-site at Heart Rhythm 22, San Francisco.

Transcript:

– I’m James Freeman, I’m a cardiac electrophysiologist at Yale and I direct our EP laboratories at Yale, and today I’ll be talking about our study on in-hospital outcomes after left atrial appendage closure with the Watchman 2.5 Device, the first generation device, and the Second-Generation Watchman FLX Device.

Importance of this study

Yeah, so the Second-Generation Watchman FLX Device was launched… It was commercially released in 2020, in August of 2020. And we really were interested in looking at the outcomes of that procedure relative to the first-generation device, in particular, looking at adverse event rates and then metrics of acute procedural success.

Key differences between the studied devices

So there were some really important differences between the two devices. Boston Scientific, essentially, closed the end of the device. And that enabled them to create a flex ball which is this atraumatic ball, when the device is partially deployed, so that you can put the device in, advance it in, and position it in multiple different ways to try and get optimal positioning. And then also the device can be easily recaptured and repositioned a number of times. They also had a couple other advancements, they have a dual row of anchors and extended a mesh coding a little further down on the device. The device was largely redesigned to try and minimise any trauma associated with placement and to decrease the rate of pericardial effusion, which was a historic Achilles heel of this procedure.

Study design and patient baseline characteristics

So, the Watchman FLX Device was commercially released beginning in August of 2020. And the way they did the commercial rollout was fairly unique. They essentially went to each site, and they asked them to turn in their inventory of the old device and use, exclusively, the new device within a month, in almost every case. And so that presented us with a really unique opportunity to do a natural experiment error analysis. So the way that worked is that at any given site if they had done 35 Watchman FLX cases, we looked at the 35 cases of the Watchman 2.5 that they had done immediately proceeding the first flex case. And so each site served as its own control, and really nothing else was changing at those sites at the time, the indications for the procedure were the same, the operators were the same, the sites were the same. There were no other big, secular trends happening at the time, and so we thought this offered us an opportunity to really get balance between the two different groups. And we ended up with about 27,000 patients, in both groups, over a relatively short time horizon. And so the result of that was that when you look at the baseline characteristics between the patients that received the Watchman FLX and those that received Watchman 2.5, the groups were essentially identical. It was a akin to what we see in a randomised trial, the difference being that we have 27,000 people in each arm. So it has all the advantages of a randomised trial and that you have real balance between the two groups, and so any differences we’re seeing are not differences associated with the groups being different but really with the procedure. We then did a secondary analysis which was a propensity-score-matched analysis. And that we took all of the Watchman FLX patients and we did matching on age, gender, propensity score, actually, up to two patients with the Watchman 2.5, and used that analytic methodology to recapitulate the same efforts to try and look at at outcomes between the two procedures.

Key findings

Yeah, so for secondary endpoints, we looked at acute procedural success metrics and we found that acute procedural success, so the number of devices that were successfully deployed and released, was higher by about a percent. And so I think that speaks to the fact that this device is a little easier to to deploy and to optimise positioning, and so I think to a big advantage. We saw a decrease in procedure time by about four minutes, associated with the new device, and we think that that’s important. And it was a non-significant finding, but different in absolute numbers, we saw a lower rate of leaks greater than five millimetres. Again, possibly speaking to the fact that we can optimise positioning of this device. Also, the device has a little more metal in it that should allow it to conform to appendages a little better in theory, and this data seems to suggest that that’s the case with some of the leak data.

Correlation between procedure volume and safety events

So the key finding is that the device is markedly safer, and the rate of major in-hospital adverse events dropped from 2.4% to 1.35%, and that was largely driven by a market drop in pericardial effusion requiring intervention. So the rate of pericardial effusion requiring intervention dropped from 1.2% to 0.4%. And that’s a really catastrophic complication with a lot of downstream consequences. So as a result, the rates of major bleeding were markedly lower, and rates of major bleeding were also lower potentially for other reasons, but we really think it was largely driven by pericardial effusion. The rate of death was cut in half so from 200,000 to 100,000. Rate of cardiac arrest decreased as well. So I think they really move the needle with this device iteration on procedural safety.

Take-home messages for clinicians

Yeah, so the key take-home message here is that the procedure has gotten markedly safer with the new device. And in particular one of the main Achilles heels of the procedure was pericardial effusion requiring intervention, and there’s just a market decrease in that catastrophic complication. So I think they’ve really changed the risk benefit calculation for patients and for physicians as they contemplate this procedure. And I think it’s really important to note that this procedure’s often done in people that are older and relatively ill. You know, the average age of people getting this procedure done in the United States is 76, the average CHA2DS2-VASc Score is is 4.6. So these are high-risk patients. So to be able to cut procedural safety, or to improve procedural safety that much is really a big deal.

Next steps

Yeah, so I think they’ll continue to be iterations of devices and whatnot. We need to look at post-procedural anticoagulation and antithrombotic strategies to try and continue to improve the safety of the procedure. We actually have some work that’s coming out on on post-procedure antithrombotic, and the ability to try and prevent bleeding in this very-high-risk population. So I think a lot of exciting work to be done in this space to try and optimise the procedure and make it even safer and better.

Dr Luigi Di Biase (Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA) joins us on-site at EHRA 2022 for a short interview on the latest updates in the precision medicine approach to atrial fibrillation. Dr Di Biase outlines the use of a precision medicine approach to post-ablation occurrences in patients with atrial fibrillation, and provides advice for clinicians.

Discussion points:
1. The precision medicine approach to AF post-ablation occurrences
2. Latest advances in this field
3. Further research required
4. Advice for clinicians
5. Take-home messages

Recorded on-site in Copenhagen, EHRA Conference 2022.
Interviewer: Jonathan McKenna
Editor: Jordan Rance

In this video interview from EHRA 2022, Dr Paulus Kirchhof (University Heart Center Hamburg, Hamburg, DE) discusses the outcomes of the EAST-AFNET 4 Study, and their applicability in clinical practice.

Discussion points:
1. An outline of the EAST-AFNET 4 Study
2. Benefits of early AF treatment
3. Observations from clinical practice
4. Take-home messages
5. Further research required

Recorded on-site in Copenhagen, EHRA Conference 2022.
Interviewer: Jonathan McKenna
Editor: Jordan Rance

Transcript:

An outline of the EAST-AFNET 4 Study

– EAST-AFNET 4 stands for early treatment of atrial fibrillation for stroke prevention trial. We all know that a healthy atrium is a beautiful, well-organized, almost aesthetic structure. And that atrial fibrillation damages this structure, and actually causes permanent damage even after a full, a few weeks of atrial fibrillation. Prior trials trying to demonstrate that restoring and maintaining sinus rhythm, so-called rhythm control therapy, improves outcomes by preventing this damage, fail to demonstrate benefit. But they actually showed that patients treated with rhythm control, as we used to do it 20 years ago, had more hospitalizations. Therefore, as a community, we have reverted back to a strategy of, give rate control to everyone initially, and then only use rhythm control to improve symptoms. Now in the trial, we tested whether a modern, systematic rhythm control therapy can improve outcomes, compared to this usual care.

Benefits of early AF treatment

Early rhythm control therapy, when delivered on top, in addition to anticoagulation and therapy of concomitant cardiovascular conditions, reduces a composite of cardiovascular death, stroke, and hospitalisation for heart failure or acute coronary syndrome by 21%. So, you can prevent every fifth event compared to usual care. This benefit is achieved without a safety signal. And one of the big take-home messages from EAST-AFNET 4, is that the trial found a way to deliver rhythm control safely. And that we can now try to implement safe ways to implement rhythm control therapy to all patients in a safe way, to achieve this current development.

Observations from clinical practice

Currently, we only offer rhythm control to one in five patients in Europe when they are first diagnosed with atrial fibrillation. And considering the efficacy and safety of rhythm control therapy as tested in EAST, I believe we should at least consider, actually offer, rhythm control therapy to all patients with newly diagnosed atrial fibrillation. It’s very simple. Whenever you think anticoagulation in a patient with atrial fibrillation, we also think rhythm control. Rhythm control therapy should be part of the management of all patients with recently diagnosed atrial fibrillation and stroke risk factors. It needs to be delivered safely.

Take-home messages

We are continuously interrogating the EAST-AFNET 4 data set. Here in Copenhagen, tomorrow, we’ll show you the data on how sex as a category, interacts with early rhythm control. At the Heart Rhythm Congress, we’ll show you some really exciting data on the interaction of multiple comorbidities with early rhythm control, trying to address the question whether we should rather treat the sick and frail patients, or those that are easily maintained in science, within the young and healthier ones. We are doing further sub-analysis, and I do believe that there is also room for additional trials, testing populations that are difficult to treat. For example, patients after acute stroke, or patients with HFpEF and atrial fibrillation.

In this short video interview filmed at EHRA 2022, Dr Dhiraj Gupta (Liverpool Heart and Chest NHS Foundation Trust, UK) discusses research surrounding atrial fibrillation in heart failure, and the considerations that must be taken when approaching AF ablation.

Discussion points:
1. Research surrounding atrial fibrillation in heart failure
2. Conflicts in this research
3. Further research required
4. Considerations when approaching AF ablation
5. Take-home messages for clinicians

Recorded on-site in Copenhagen, EHRA Conference 2022.
Interviewer: Jonathan McKenna
Editor: Jordan Rance

Transcript:

Research surrounding atrial fibrillation in heart failure

– So atrial fibrillation and heart failure are the two global pandemics in the cardiovascular arena. They both tend to worsen the outcomes of each other. And so there’s been lots of interest in improving those outcomes over the last 20 years or so. Historically, the rhythm control strategy used to involve cardioverting these people and giving them anti-arrhythmic drugs, and the historical trials show no difference with that strategy and no improvement. More recently, with catheter ablation, the chances of maintaining sinus rhythm are much higher. And hence, there’ve been lots of head to head, randomised control trials, which have addressed this very issue.

Conflicts in this research

So it’s very difficult to know in an individual patient what best to do because it’s such a wide spectrum of patients. There are some people in whom atrial fibrillation is the fundamental reason for the heart failure or at least it’s contributing to the heart failure. And it’s those patients who you really want to address with ablation. Equally, there are some patients in whom atrial fibrillation happens as a byproduct of longstanding heart failure, almost as a end-stage disease. In them, there’s little to gained by doing catheter ablation. So far, on the trials I have done have not made a distinction between these two subtypes. So essentially, all-comers with heart failure and atrial fibrillation have been included in these trials.

Further research required

The most important thing we need is to identify those patients with atrial fibrillation and heart failure who are likely to benefit from rhythm control with catheter ablation. So you are enriching that population and making the risks and the expense of catheter ablation worthwhile in these patients.

Considerations when approaching AF ablation

So, the most important thing to consider is that patients with congestive heart failure are very different from your usual AF ablation population. These patients are often sicker. They’re often older, they have lots of co-morbidities. So the risk of complications is much higher. So you need to be aware that you’re bringing your A game to the table when you’re doing AF ablation in these people. So you need to do, you need to use your best technology. You need to be minimalistic in terms of what you can achieve because these patients often cannot tolerate long procedures and you need to be realistic in your expectations.

Take-home messages for clinicians

Well, first of all, be aware that now there are good quality data showing that rhythm control with catheter ablation improves outcomes in these patients. So often, these patients feel better. They have better objective criteria for performance, such as six-minute walk distance, levels of NT-proBNP levels. And often, they live longer as well. If you follow up these patients long enough. So the awareness is key and that education needs to be disseminated all through the, to the primary providers and secondary providers.

In this short late-breaking interview, Dr Jason Andrade (Vancouver General / Montreal Heart Institute, Montreal, CA) joins us at EHRA 2022 to outline the findings of a meta-analysis of EAST-AFNET 4. The main outcomes suggest that early rhythm control therapy is beneficial for AF patients, reducing their cardiovascular outcomes.

Discussion points:

1. Reasoning behind this meta-analysis
2. Study design and patient population
3. Key findings
4. Take-home messages
5. Further research required

Recorded on-site in Copenhagen, EHRA Conference 2022.
Interviewer: Jonathan McKenna
Editor: Jordan Rance

Transcript:

So, when we think about early rhythm control, we want to know that it has a comprehensive effect.

So, we know that ablation is good at getting rid of atrial fibrillation, but if it doesn’t get rid of other things that come along with it, it’s not very valuable as a first therapy.

So, we look at early rhythm control. We want to know that it also reduces hospitalizations, healthcare utilizations, that it doesn’t come with a cost of increasing complications, and that it does improve quality of life.

And so, when we’re faced with a treatment decision, we want to know whatever intervention that we do is going to benefit each of those outcomes.

So, the study design was a meta-analysis of the three first line cryoballoon catheter ablation studies.

So, we took the year European Cryo-FIRST study, the American STOP AF First study, and the Canadian EARLY-AF study. We combined all 750 patients into one meta-analysis, which gave us the power to look at healthcare utilisation outcomes, as well as quality of life outcomes.

The key finding of the meta-analysis was that first-line catheter ablation significantly reduced arrhythmia recurrence and arrhythmia burden. That led to an improvement in quality of life compared to medical therapy, which led to a reduction in hospitalisation, emergency room visits and cardioversions in the year following intervention.

So, the take-home message from this study is that we now know the comprehensive effects of a first-line catheter ablation approach.

So, when we’re faced with a patient with newly diagnosed atrial fibrillation, our treatment choice of medical therapy versus catheter ablation, we now know that on all fronts, catheter ablation is better. It reduces arrhythmia recurrences; it improves quality of life and patients are less likely to come into hospital in the year following intervention.

So, the further research that’s required is to look at how this lasts over time.

So, all of these studies are looking at the year following intervention, and we can say that as a comprehensive first-line therapy, ablation’s better.

What we would like to know is whether ablation actually modifies the disease and whether that leads to long-term benefits for these younger patients with atrial fibrillation.

In this late-breaking interview filmed at EHRA 2022, Dr José Merino(Hospital Universitario La Paz, Madrid, Spain) discusses the findings of the POWER-FAST III trial, a study that aimed to compare atrial fibrillation ablation strategies of conventional radiofrequency ablation and high power radiofrequency ablation.

Results suggest that PVA was achieved in both cohorts, with no significant differences between the techniques.

Discussion Points:

1. Aim of this study
2. Patient population and study design
3. Main findings
4. Take-home messages
5. Further research required

Recorded on-site in Copenhagen, EHRA Conference 2022.
Interviewer: Jonathan McKenna
Editor: Jordan Rance

Transcript:

Hello, my name is José Luis Merino. I am working in La Paz University Hospital, in cardiac electrophysiology. So, I’m heavily involved mostly in ablation, but, also in other kinds of procedures. Okay, the aim of the POWER-FAST III Trial was twofold, because we tried first, to prove that high-power, short-duration (HPSD) (ablation) was safe, or at least as safe as a conventional approach. And the second was, that we tried to prove that HPSD may result in better efficacy in talking about less AFib recurrences, or atrial arrhythmia recurrences at one year, follow-up. Always compared with a conventional way of doing RF application.

Yeah, the study design and patients that we enrolled in the trial is simple. We enrolled patients with both, or either, persistent, or paroxysmal atrial fibrillation. There were no significant exclusion criteria for prior AFib ablation or recent cardiac surgery, for example, among others. And then, the design of the study was also simple. We randomised one-to-one patients to both arms, conventional or hyper circulation RF application, and there, a patient undergo ablation, and the following day, they had an oesophageal endoscopy taken. Then, patients were followed for one year with both onsite visits, on-demand visits, in case they have symptoms and daily ECG transmissions. That is one of the strengths of this study.

Although, here in the EHRA congress, we just presented the acute results of safety and acute efficacy results.

The main findings in this study were first, as I said, we have to consider the aims. So, safety in one side, and efficacy. In terms of efficacy, we found that PVI was of course achieved with both techniques in almost all patients in all veins, with no differences between the two groups. In terms of first-pass isolation, surprisingly, we found that it was more easily achieved with the conventional approach than with high-power, short-duration.

In other efficacy or procedural-related endpoints like procedural duration and fluoroscopy, for example, there were no significant difference between the two groups. In terms of safety, we found no differences in oesophageal damage. It was quite similar, around 6% in both groups. And, in other complications again, there were no differences between the two arms. Although, we had a slightly trend towards a more tamponade and more systemic embolism in the high-power, short-duration arm.

The main take-home message is that in both techniques, HPSD can be done in terms of efficacy. In terms of oesophageal damage, it appears to be safe. It was one of the concerns, by using this technique in the posterior wall of the left atrium. But still, there are pending issues like this trend of potential complications that need to be clarified, probably with more research and other trials. Yes, we’re in the process, first off because we were presenting acute results. So, now we need to wait until we have the follow-up. So, in order to see if these results in at least similar recurrences, but it maybe that we find less or even more, because maybe this technique is very fast but produce less deep lesions. So, we have to wait for that. In addition to that, I think that we need to further explore the safety of the procedure, especially not the oesophageal, that appears to be safe, but the temporary risk and the embolic risk.

In this short interview recorded at EHRA 2022, Dr Marco Schiavone (Luigi Sacco University Hospital, Milan, IT) outlines the findings of a real-world meta-analysis designed to assess the clinical outcomes of S-ICD in HF patients from the largest European Registry. Results suggest that over 2 years, there were no significant differences in appropriate and inappropriate shocks between patients with and without HF.

Discussion points:
1. Importance of this analysis
2. Study design and patient population
3. Key findings
4. Take-home messages
5. Further research required

Recorded on-site in Copenhagen, EHRA Conference 2022.
Interviewer: Jonathan McKenna
Editor: Jordan Rance

Transcript:

– Hello, I’m Marco Schiavone. I’m actually a young cardiac electrophysiologist working at the Luigi Sacco University Hospital in Milan.

Importance of this analysis

The importance of this analysis on heart failure patients in S-ICD is that we don’t have specific data on this kind of population. We just have one trial which is the UNTOUCHED trial that basically show that this device is a very good device in this kind of population. And so with our large retrospective registry, we try to find out if this data were confirmed and actually, if this kind of patients will ever benefit from this device.

Study design and patient population

The study design is retrospective registry which is the largest retrospective registry on the S-ICD in Europe. We basically enrolled 1,400 patients that were all analysed retrospectively.

Key findings

The key findings, are that the key findings of our study are that this device is a device that did not suffer from a higher number of inappropriate shocks, when we compared the heart failure population versus the no heart failure population. So, basically the primary outcome of our study was the rate of inappropriate shocks. So, we included in the HF population, patients the heart failure and reduced and mildly reduced ejection fraction. Then we compared then with no nerve failure population. And we found that in these two, basically cohorts, we did not found the different numbers of inappropriate shocks. As for secondary outcomes, we found that as for device related complications, heart failure patients suffer from a slightly higher number of device related complications but those complications were always or almost always managed in an easy way and so patients did not suffer from a worse outcome in the heart failure population. So, this device is kind of safe and effective in this particular setting.

Take-home messages

The take-home message of our study is that we can actually use this device in heart failure patients, because there’s an idea that maybe this device is suitable and very adequate for the young patients not suffering from several comorbidities while often heart failure patients, do need a transvenous device, but this is not completely true and our study confirms that, of course heart failure patients may need CRT in cases of left bundle branch block and need for CRT. Sometimes they also may need pacing. And of course in that case, a transvenous device will be needed. But in all other case when CRT, ATP or pacing is not needed the subcutaneous ICD is a very good device in this kind of setting. And we always have to keep in mind that whenever in the follow up a heart failure patients are going to need for pacing or CRT, you can just extract the S-ICD device without, complications in most cases and you can always upgrade to a transvenous device in the future.

Further Research

Sure, we need further research with the randomised trial that may confirm our study in a prospective and in randomised setting and actually a randomised trial will always be better in results than a retrospective analysis. But I think that we just opened a road for further research and of course even sub-analysis of the PRAETORIAN trial or other randomised trial, will give us a definite answer on the question. Whenever the heart failure setting will be investigated by other groups or also by our groups, sometimes we’re going to make a randomised trial.

Dr Phillip S Cuculich (Washington University, St. Louis, MO, US) shares the longer term results from a Phase I/II Study Of EP-guided Noninvasive Cardiac Radioablation for Treatment of Ventricular Tachycardia.

HRS 2020:Recorded remotely from Washington.

Interviewer: Mirjam Boros
Recording editor: Natascha Wienand

Transcript Below:

My name is Phillip Cuculich, and on behalf of my colleagues and collaborators here at Washington University School of Medicine, in St Louis, I’m honoured to share with you the results from the longer term follow-up of our phase I/phase II study of EP-guided noninvasive cardiac radioablation for the treatment of ventricular tachycardia. A study that we call ENCORE-VT.

Now as heart rhythm specialists, many of us at HRS perform procedures with catheters. We carefully manoeuvre these within and around the heart, meticulously trying to find the critical short circuits of electricity. Once those circuits are identified and discovered, we apply energy at the tip of the catheter which creates heat, to destroy the electrical conduction through these circuits.

However, heat from a catheter is limited, and often we can’t reach the deeper elements of the circuit within the heart muscle, and so our procedures can fail. To deliver a full thickness, gap free ablation we look to our radiation oncology colleagues. That’s right, our cancer doctors, who have the exact same goals when they’re trying to treat tumours.

Now, in the basement of most hospitals you’ll find cancers being treated with stereotactic body radiotherapy, or SBRT. Now this concept, x-rays or photons are delivered by a robotic arm in sweeping arcs around the patient delivering high doses of ablative energy to a tumour with minimal exposure to the surrounding tissues. In short cardiac radioablation we simply treat an arrhythmia circuit like a tumour.

In 2007 we reported the first case series using focused cardiac radioablation in five patients, with refractory VT. Based on these results we opened a formal prospective phase I/phase II trial to answer the following question: In patients with VT, who have failed conventional therapies, can a single non-invasive radiation treatment safely reduce VT burden?

Now, the long term results of this trial are shared here, at HRS 2020. So who was included in this study? In general, the 19 patients in this trial had weak hearts, and advanced cardiomyopathy. They had a median of 96 episodes of VT requiring rescue from their defibrillator in the six months before the treatment. And all of them had failed standard therapies such as anti-arrhythmic medicines, or catheter ablations.

Overall, compared to other clinical trials of catheter ablations, this was a very sick patient population. And the median target size for ablation was 25 cc, and to provide some element of reference, a golf ball is about 45 cc. But after we account for the cardiac motion, and the respiratory motion, and set up uncertainties, the actual treated volume was more than 90 cc, and their median treatment time was only 15 minutes.

The first question that we sought to answer, is this safe? And the answer appears to be yes. We’re now reporting the results from the past three years. The treatment itself is short and entirely noninvasive. There were no problems with the cardiac devices, both during and after treatment, and patients are treated as outpatients. So literally they get up after treatment and they walk out of the treatment unit and go home.

In the first 90 days of analysis, one patient developed inflammation of the pericardium, called pericarditis. And this was treated successfully with a short course of oral steroid medication. Over the next three years we saw two more patients who had developed fluid around their heart; called a pericardial effusion. And both of these were easily treated with colchicine and anti-inflammatory medication.

Importantly one patient developed a gastropericardial fistula, just after two years after treatment. And this was very near the area that we had treated in the heart, on the inferior wall of the left ventricle. This patient presented with abdominal pain, we were able to make the diagnosis quickly, and this patient underwent a successful corrective surgery. Now to date, no patients have developed heart block, there’s been no coronary artery injury, there’s been no cardiac perforation.

In general this appears to be a gentle ablation for patients. And this is reflected, I think, in the overall survival. When you look at six months, in this very sick population, 89% of patients were still alive at six months. Which is really superb when you think about this patient population. And over half the patients remain alive at two years.

Now what about the second question, is it effective? Well in this study, this is the first formal study, we chose to look at any reduction in VT burden as our primary endpoint. Now we compared the six months before treatment to the six months after treatment. So at six months, 94% of our patients met the trials primary endpoint, and then continuing out to two years, which we’re reporting here, 78% of patients continued to meet that primary end point of VT reduction.

Again, that’s not a fair comparison of 24 months after to the six months before, and yet the numbers are still fairly impressive. Now it’s important to put this into some context though. Most patients were not free of VT, we were not seeking to cure VT with this. It’s a difficult bar to achieve in a salvage patient group, and that wasn’t the purpose of our study. We will report a number of pre-specified secondary endpoints, and perhaps the most impactful for patients, in the six months after treatment, 78% of patients did not have a single ICD shock, and this was in the face of de-escalating anti-arrhythmic medicines. Many patients were off anti-arrhythmics entirely. So in conclusion this report is really the first long term follow-up of noninvasive cardiac radioablation, which is critical, because we know radiation can have late adverse effects. And in patients with VT, who failed conventional therapies, a single noninvasive 15 minute focused radiation treatment safely reduced VT burden. And this effect persisted beyond two years for most patients. So far, the serious toxicities appear to be low, but they can occur out to two years and beyond, so long term vigilance is really needed for future trials. And so right now, based off of these results, presented here at HRS 2020, we believe that cardiac radioablation is currently best suited for high risk patients who have failed conventional VT therapies.

Question: How should this study be built upon?

Well I think as we’ve looked past the last three years now, we’ve seen multiple case reports, and now four different case series published, that have all generally shown the same thing. That with a single dose of cardiac radioablation, we see a dramatic reduction, and a relatively early reduction in VT burden, in some of the worst cases. This now needs formal follow-up, in a prospective randomised trial, and we’re organising this trial now, with the hopes of opening this in Q1 2021.

Dr Vivek Y Reddy (Icahn School of Medicine at Mount Sinai, New York, NY, US) shares the results of the Point-by-Point Pulsed Field Ablation (+/- Radiofrequency Ablation) to Treat Atrial Fibrillation: A First-in-Human Trial.

The trial looked at tissue selectivity of pulsed field ablation (PFA), which provides safety advantages over radiofrequency ablation (RFA) in treating AFib.

Questions
1. What is pulsed field ablation (PFA) and what is its potential?
2. What data are you presenting at HRS 2020?
3. What did the data show?
4. What further research should be conducted with this technology?

HRS 2020: Filmed remotely from New York.

Interviewer: Mirjam Boros
Recording editor: Natascha Wienand

Dr Atul Verma (Southlake Regional Health Center, Toronto, ON, CA) on behalf of the PULSED AF Investigators shares the results of a study measuring the safety and effectiveness of the novel Pulsed Field Ablation (PFA) technology.

Dr Verma tells us about the difference between Pulsed Field Ablation (PFA) and Point-to-Point pulsed ablations and talks about the future plans for this technology.

Questions:
1. What technology was used in this study and how does it differ to point-to-point pulsed ablations?
2. What was the design of the trial?
3. What did the data show?
4. What further research should be conducted with this technology?

HRS 2020: Recorded remotely from Toronto.

Interviewer: Mirjam Boros
Recording Editor: Natascha Wienand

Transcript Below:
[Verma] I’m Dr Atul Verma. I’m the medical director of the Heart Rhythm Program at Southlake Regional Health Center and also associate professor at the University of Toronto in Canada. I think that electroporation has the potential to really revolutionise what we are doing in the electrophysiology. I’m very proud to be working with this technology and I really want to thank all my co-investigators and the team at Medtronic for designing this wonderful technology.

Question 1: What technology was used in this study and how does it differ to point-to-point pulsed ablations?

[Verma] It was a pleasure to present the PULSED AF trial at HRS Late-Breaking. What differentiates this technology from traditional point-to-point radio frequency is that it is called pulsed field ablation or irreversible electroporation. So instead of using thermal energy, like heat or freezing, we are using electrical fields and when we expose them to the tissue, that opens up pores in the cells, which then leads to targeted cell death. So this is a non-thermal ablation. And we think that this will offer many advantages over traditional point-to-point radio frequency.

Question 2: What was the design of the trial?

[Verma] So the data that we’re presenting for the PULSED AF trial are essentially the initial acute results of the trial. So we were meant to evaluate 20 patients but we reported on 14 because the other six cases were differed because of the COVID-19 crisis. But what we’ve showed was essentially the primary safety endpoint, which is whether there were any safety issues within the first 30 days and the primary acute efficacy endpoint, which was the ability to isolate the pulmonary veins using the pulse field ablation only and no other technologies.

Question 3: What did the data show?

[Verma] I’m proud to say that when it came to safety, we certainly had no seriously adverse events reported thus far in the trial. In particular, we think that pulse field ablation will have a better safety profile when it comes to phrenic nerve injury or esophageal injury, and certainly we saw no change in the esophageal temperature in the patients. And we also so no phrenic nerve injury and there were no other serious adverse events reported at 30 days. And for the acute efficacy endpoint, we were able to isolate a 100% of the pulmonary veins in the 14 patients using pulse field ablation alone and no other technologies.

Question 4: What further research should be conducted with this technology?

[Verma] So obviously, there is further research that needs to be conducted with pulse field ablation. First of all, we’re going to be following all of these patients out to one year and we will be reporting at on one year efficacy and safety endpoints. Furthermore, we obviously need a larger trial with more numbers of patients. This was just a first in human feasibility trial and we hope to be moving into a much larger pivotal trial very, very soon.