Leadless pacemaker technology is expanding to dual-chamber pacing

Two late-breakers at Heart Rhythm 2023 highlighted new, miniaturized, implantable EP device technology to expand the use of leadless pacing. By eliminating the lead wires connecting pacemakers to the inside of the heart, it removes the biggest potential complications of lead fractures and limits infections of the wires or the surgical device pocket. Leadless devices also eliminate the need to remove old leads during future device battery replacements. This takes what was once an open surgical EP procedure and enables it to be an interventional procedure completed using catheters.

The most significant advancement in leadless pacemakers since their introduction to the U.S. market in 2016 was the late-breaking Aveir dual-chamber i2i pivotal trial at Heart Rhythm 2023. The study looked at the safety and efficacy of percutaneous implantation of a dual-chamber leadless cardiac pacemaker system with bidirectional communication for atrioventricular synchrony between two Abbott Aveir devices. 

This trial was positive for both safety and efficacy, and it could pave the way to greatly expand leadless pacing. Until this trial, leadless pacemakers have been limited to single-chamber pacing, which is limited to just 10-20 percent of patients who need a pacemaker. About 80% of patients require dual-chamber pacing. The positive data from this trial has already been submitted to the FDA for review. If this new pacing system is cleared by the FDA, it would greatly broaden access to leadless technology for all patients.

"It is truly exciting that we are going tom have a dual-chamber implantable pacemaker, that is amazing. That is where things seem to be going," Ellenbogen explained.

In another late-breaker, the SOLVE-CRT study evaluated a new leadless pacemaker technology that can deliver cardiac resynchronization therapy (CRT) among patients who were not able to be treated with conventional CRT and epicardial leads. The EBR Systems WiSE technology connects a traditional implanted pacemaker to a subcutaneous ultrasound emitter. Rather than using wire leads, the emitter sends pulses of ultrasound energy and a tiny implanted electrode the size of a grain of rice inside the heart, which coverts the signals back into electrical pulses to pace the heart. The device worked much better than the pre-determined goal set for preventing reverse remodeling.

Late-breaking EP studies positive for conduction system pacing 

"One of the biggest areas of development is conduction system pacing," Ellenbogen explained. He said this was clearly one of the biggest trends being discussed in both sessions and in late-breaking trials where the new method was compared to the current standard of care.

Ellenbogen said conduction pacing is being heavily researched as an alternative to traditional coronary sinus pacing, which is designed to replicate the natural human conduction system inside the heart. This entails placing pacemaker leads directly into the bundle of His to restore normal sinus rhythm prevented by left bundle branch block (LBBB). 

There were three late-breaking clinical studies highlighting the success of left bundle branch area pacing (LBBAP), or His-bundle pacing (HBP), as an alternative to the standard of care. The HOT-CRT trial found greater improvement in left ventricular ejection fraction with HBP CRT compared to biventricular pacing (BVP). The late-breaking results from the International LBBAP Collaborative Study Group supported LBBAP also showed the new technique is a promising alternative, and may result in superior resynchronization compared to the traditional BVP. 

New tools and research on AFib catheter ablation

New technologies in the EP lab in recent years have helped greatly reduce the time required and the accuracy of mapping and ablation procedures to treat atrial fibrillation (AFib). Just a few years ago, about one-third of patients who went in for an ablation procedure needed a second procedure because of incomplete isolation of the pulmonary veins. However, Ellenbogen said the new technologies have helped reduce procedure times and boost efficacy. 

"We are now seeing dramatic reductions in the need for repeat procedures. There is a lot of buzz at this meeting about catheter ablation of AFib, and there is a lot going on," Ellenbogen said. 

This includes not only the growing use of cryoballoon ablation, but also several studies on the use of pulsed field ablation (PFA). PFA is widely expected to become a new standard of care in ablation therapy if clinical trials show it is both safe and effective. So far, the results from trials have been very positive. While the efficacy between the current ablation technologies and PFA are about the same, the safety profile of PFA is much better. The technology has significantly fewer complications due to burn through to sensitive, underlying tissue like the esophagus and phrenic nerve. The safety profile alone is very appealing to most EPs, but Ellenbogen said there is also positive data to suggest PFA might have better long-term ablation outcomes as well. There were three late-breaking studies of pulsed field ablation at Heart Rhythm 2023.

"Every company is coming up with ways to ablate AFib better, quicker and safer. So, this makes it harder and harder not to offer patients ablation as a first-line therapy. In fact, with paroxysmal AFib, I think more and more for EP labs, catheter ablation is becoming the first line therapy," Ellenbogen explained. 

He said these decisions are based on data, including additional positive data presented this year at HRS 2023. 

Another late-breaker that Ellenbogen described as "phenomenal" looked at the use of the diabetes drug liraglutide to help patients lose weight prior to cardiac ablations. He said it led to profound, positive outcomes in lowering AFib reoccurrence.

"In patients who lose more than 3% of their weight, the amount of AFib they have after an ablation is markedly decreased. So perhaps this is a pharmacologic addition to catheter ablation that can help improve our success," Ellenbogen explained. 

The rise of remote monitoring and AI's role in reading ECGs

Ellenbogen said another big trend evident in sessions, late-breaking studies and on the expo floor is the replacement of traditional Holter monitors with small, wearable patch cardiac monitors. These now have wireless connection to the patient's smartphone where an app sends the data to a monitoring company, or directly to the physician's office. Mobile cardiac outpatient telemetry (MCOT) monitoring has become one of the major trends in electrophysiology.

Artificial intelligence (AI) is also starting to play a rapidly increasing role to keeping an eye on these remotely monitored patients and alerting human clinicians when there are serious events. Ellenbogen said the AI is also being used to dig through days or weeks worth of continuous 24-hour monitoring data to quickly identify various types of arrhythmias and generate detailed reports. This can save clinicians a vast amount of time that would otherwise be required to comb through that data manually. 

Another major advance in AI is using it to assess thousands of data points in ECG signals to identify patterns not evident to the human eye. These patterns can predict future arrhythmias like AFib, or episodes of ventricular tachycardia (VT) that can lead to sudden cardiac death. In one late-breaking study at HRS this year with more than 100,000 patients, an AI algorithm could accurately predict future events with 88% accuracy. 

"Monitoring remotely with MCOT with the ability to watch the telemetry and the use of AI has become a bigger and bigger thing, as you can see on the expo floor with all the companies offering this technology," Ellenbogen explained.  

Many consumer-grade wearables and smartwatches also now incorporate single-lead ECG and AI interpretation algorithms. While this have helped with screening more patients for arrhythmias in the general population and it has the potential to catch things earlier, it also results in an increased number of false positives, which can burden clinicians. 

Integration of data from traditional 12-lead ECG, wearables, Holter and implantable EP devices into a central location has become a priority for many healthcare organizations so the data is easier to access and manage. Ellenbogen said there is no standard of care on how to do this just yet, but integration has the ability to make EP workflows more efficient. 

He said there also are questions about which technologies for long-term recording of AFib burden are best. Small implantable monitors that can last three or more years were seen as the new standard of care. However, Ellenbogen said some smartwatches today can record with the same level of accuracy for AFib burden non-invasively, so things may change in the coming years. 

Additionally, Ellenbogen said at least one vendor has come up with an AI algorithm to look at ECGs to create detailed, noninvasive electromapping of the heart that can be used to determine the source of arrhythmia. This may play a role in being able to pre-plan and shorten ablation procedure times. 

End of COVID pandemic brought HRS almost back to pre-pandemic numbers

Just before the interview, two old friends of Ellenbogen saw him and came over and gave him a big post-COVID hug. Ellenbogen said that in itself speaks volumes to a big trend worth mentioning—a return to normalcy after three years of the pandemic impacting in-person conferences.

"It is great to be out without masks. We have almost as many people here as we had pre-COVID. We are coming out of COVID and I couldn't be happier," he said.

There were very few masks being worn at the conference and there was a general sense at the conference that things are moving back to normal. The event had the feel of pre-2020 medical conference.

Attendance for HRS 2023 was more than 8,400. This included about 7,900 in-person attendees and more than 500 online only. There were nearly 1,500 first-time attendees this year and more than 1,000 in-training attendees and students. 

Attendees this year came from 90 countries, another sign the pandemic is over, as international in-person attendees were largely absent at most of the cardiology meetings during the pandemic.

This year's meeting featured more than 200 sessions and included 114 exhibiting companies on the expo hall floor.

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