Almost 70% of patients treated with a leadless left ventricular (LV) endocardial pacing system had a favourable clinical response at six months, a post-market surveillance registry has shown.
The findings were published in Heart Rhythm. Authors Benjamin J Sieniewicz (St Thomas’ Hospital, London, UK) et al say that response rates are equivalent to lead-based biventricular endocardial pacing systems, while largely eliminating the risk of thromboembolic stroke. But, they add: “Implantation of the system can be associated with a significant complication rate; however, as operators gain more experience with the delivery system, complications become less frequent.”
The researchers describe the WICS-LV Post Market Surveillance Registry as the “largest experience to date of this novel technology to achieve leadless LV endocardial pacing”. The registry was designed to assess the procedural success, safety and chronic efficacy of leadless LV endocardial pacing in a real-world setting.
In all, 90 patients across 14 European centres underwent implantation with the WiSE-CRT System (EBR Systems). Patients were predominantly male, aged 68.2±10.5 years, and had a left ventricular ejection fraction (LVEF) of 30.6%±8.9%, a mean QRS duration of 180.7±27ms, and ischaemic aetiology in 40%.
Successful implantation and chronic delivery of biventricular endocardial (BiV ENDO) pacing was achieved in 94.4% of patients. Device/procedural related adverse events occurred in a “significant number” of patients, say the authors. There were three (3.3%) procedure-related deaths within the study; 4.4% of patients suffered a procedural complication within 24 hours of the procedure, 18.8% between 24 hours and one month, and 6.7% between one and six months. At six months, 70% experienced an improvement in heart failure symptoms.
Sieniewicz et al report that the most common procedural complications were related to femoral arterial access, “as the WiSE CRT system was designed to allow the deployment of the pacing electrode in the LV cavity via retrograde aortic access from the femoral artery. This required large bore 12 Fr femoral arterial access and closure, a skill not commonly required by practising electrophysiology/complex device specialists who tend to implant this system.”
They note that three approaches have been devised to reduce the rate of femoral arterial access complications. “Firstly, vascular closure devices were employed at 12 centres to minimise bleeding and ensure effective arterial closure was achieved at the end of the case. At 11 centres, the Perclose ProGlide (Abbott Medical) vascular suture system was used. At one centre, the Prostar XL (Abbott Medical) percutaneous vascular surgical system was used to assist vascular haemostasis. Vascular closure systems have been shown to reduce time to haemostasis.” Finally, the authors report that a transseptal approach has also been developed allowing electrode deployment following femoral venous access. This approach, Sieniewicz indicated to Cardiac Rhythm News, is likely to become “the default way the electrode will be delivered” in the future.
Writing in Heart Rhythm, the investigators conclude that BiV ENDO pacing with the WiSE-CRT System “appears technically feasible, with a high success rate”. However, they recommend: “Implantation should occur in centres with on-site cardiothoracic surgical facilities, given the risk of cardiac tamponade which may require urgent repair. Our results would suggest that endocardial CRT pacing with this novel pacing system is an effective treatment for a high risk group of patients with heart failure who either cannot receive or who have not responded to conventional CRT, and should be performed with adequate operator training in centres with experience in dealing with vascular and cardiothoracic complications.”