First-in-man study shows promise with leadless pacing


At the Heart Rhythm Society (HRS) in Denver, USA, (8–11 May), Vivek Reddy, Mount Sinai School of Medicine, New York, USA, told delegates that leadless right ventricular cardiac pacing is feasible. According to the results of the LEADLESS study, he said: “This is a relatively small feasibility study, but raises the possibility of eliminating what has been the weak link in pacemakers: The lead.”

The objective of the LEADLESS study was to investigate the percutaneous in vivo placement of a novel intracardiac leadless cardiac pacemaker (manufactured by Nanostim). He added that, although the current technology with leads is “highly mature and reliable”, the leads can cause mechanical failures, infections, and may need extractions and mobility restrictions and further noted that they are incompatible with magnetic resonance imaging (MRI).

Reddy highlighted that over 700,000 people globally were implanted with cardiac pacemakers and 50,000 of those people have experienced post-implant related problems.

He addressed the need for leadless pacemakers and said that the benefits of them were: catheter-based delivery, high-density energy source, low-power electronics, novel communication scheme, biocompatible materials, dependable fixation design and retrievable capability. He added that, because of device miniaturisation, the leadless pacemaker can be implanted percutaneously with an 18F introducer and catheter through the femoral artery. It remains self-contained in the right ventricle with the additional options of retrieval and conversion to traditional pacing leads.

Reddy then went on to speak about the results of the LEADLESS study, a prospective, non-randomised, single-arm, multicentre feasibility study to evaluate the performance of the new leadless cardiac pacemaker. He added that follow-up included a post-procedure X-ray and visits at two weeks, six weeks and three months. The indications for implantation, according to Reddy, were chronic atrial fibrillation and a second- or third-degree block (60%), sinus rhythm with low activity or short lifespan (24%) and infrequent pauses and unexplained syncope (28%).

According to Reddy, the study showed a success rate of 97% (out of 32 patients). In terms of adverse events, there was one minor groin haematoma, which required no treatment, and one cardiac perforation and tamponade which led to stroke and death.

Pacemaker retrieval was needed in two patients and was successful. He said that in the first patient, the device was retrieved and another pacemaker was implanted successfully. In the second patient, the device was retrieved successfully and an implantable cardioverter defibrillator (ICD) was then implanted.

Reddy told the audience that commercialisation of the device is expected to start later this year. He also added that a large multicentre US investigational device exemption (IDE) study is expected to start “hopefully” in 2014 and that an atrial leadless cardiac pacemaker for multi-chamber cardiac pacing is in development.