SOLVE-CRT: Leadless pacemaker can deliver CRT to people not suited for traditional systems
Key takeaways:
- A leadless pacemaker can deliver cardiac resynchronization therapy to patients who cannot have conventional CRT systems.
- The device beat safety and efficacy performance goals.
A leadless, ultrasound-based endocardial pacing system was able to deliver cardiac resynchronization therapy to patients unable to be implanted with conventional CRT devices, researchers reported.
Results of the prospective, multicenter SOLVE-CRT study of the system (WiSE CRT, EBR Systems), which was partly randomized and partly single-arm, were presented at Heart Rhythm 2023.
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“The system needs a co-implant device which can pace the right ventricle, but in conjunction with that, we implant a receiver electrode endocardially either transeptally or through the aorta into the left ventricle,” Healio | Cardiology Today Editorial Board Member Jagmeet P. Singh, MD, DPhil, FACC, FHRS, founding director of the Resynchronization and Advanced Cardiac Therapeutics Program at Massachusetts General Hospital and professor of medicine at Harvard Medical School, said in an interview. “This receiver electrode converts the ultrasound energy into electrical energy to pace the left ventricle. Alongside this, there is a battery with a transmitter implanted in the subcutaneous space, and the transmitter sends the ultrasound waves to the receiver electrode, where it gets converted to electrical energy. This is a very different cardiac resynchronization system that is leadless, that is disruptive in the use of ultrasound energy and that allows for personalized targeting of the LV electrode within the endocardium to achieve the best resynchronization.”
The study was supposed to be a randomized trial of 350 patients who were nonresponders to CRT therapy; who had not been treated, possibly due to acute or chronic lead failure; or who were undergoing high-risk upgrades from implantable cardioverter defibrillators. In March 2020, enrollment was halted due to the COVID-19 pandemic, by which point 108 patients had been implanted with the device and randomly assigned to treatment (device switched on) or control (device switched off) groups. During the pandemic, the FDA allowed the researchers to enroll as many as 192 patients from the untreated or high-risk upgrade categories in a single-arm study, Singh said during a presentation.
The present analysis included safety data from 183 patients (all 108 from the randomized trial and the first 75 from the single-arm study; mean age, 68 years; 23% women) and efficacy data from 100 patients (25 from the randomized trial who were in the untreated or high-risk upgrade categories and assigned to the treatment group and the first 75 from the single-arm study). Imaging was assessed by a masked echocardiography core lab and events were assessed by an independent adjudication committee.
“What untreatable means is that conventional CRT is oftentimes limited by the inability to implant the coronary sinus lead,” Singh told Healio. “Or patients can be very high-risk upgrades because they may have veno-occlusive disease, and therefore extracting and implanting a new or upgraded system may be challenging.”
The primary safety endpoint, freedom from type I complications at 6 months, was met in 80.9% of patients, beating the performance goal of 70% (P < .001), according to the researchers. Of the patients who did not meet the safety endpoint, 12 had a device-related event, five had a vascular event, three had a stroke or other thromboembolic event, seven had cardiac perforation and 12 had a pocket event.
The primary efficacy endpoint of decrease in LV end-systolic volume at 6 months was –16.4%, beating the performance goal of –9.3% (P = .003), according to Singh and colleagues.
“There was significant evidence of reverse remodeling, with changes in the end-systolic and end-diastolic volumes, along with an improvement in ejection fraction,” Singh told Healio. “Alongside this, there was an improvement in multiple clinical secondary endpoints, including a quality of life score and change in the QRS, which decreased in width by a mean of 39.3 milliseconds.”
Singh told Healio that “the real excitement lies in the potential clinical implications that this technology may have. One is that conventional resynchronization technology involves putting three leads in the heart, but now, you can potentially do leadless CRT without a single lead in the heart, using the WiSE CRT system in conjunction with a leadless pacemaker on the right side of the heart. In addition, there is a lot of interest in conduction system pacing, and what the WiSE CRT system allows is to directly access the conduction system through the left ventricle, where it is actually located. There is a lot of excitement about refined targeting and individualizing therapies in the future. This system certainly provides the opportunity to do that.”
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Singh JP, et al. Late Breaking Clinical Trials and Science – Registry – CIED. Presented at: Heart Rhythm 2023; May 19-21, 2023; New Orleans (hybrid meeting).