State of the art of leadless pacing

Abstract

Despite undisputable benefits, conventional pacemaker therapy is associated with specific complications related to the subcutaneous device and the transvenous leads. Recently, two miniaturized leadless pacemakers, Nanostim™ (St. Jude Medical) and Micra™ (Medtronic), which can be completely implanted inside the right ventricle using steerable delivery systems, entered clinical application. The WiCS™-cardiac resynchronisation therapy (CRT) system (wireless cardiac stimulation for CRT, EBR Systems) delivers leadless left ventricular endocardial stimulation for cardiac resynchronization. In addition to obvious cosmetic benefits, leadless pacing systems may have the potential to overcome some complications of conventional pacing. However, acute and long-term complications still remains to be determined, as well as the feasibility of device explantation years after device placement.

Leadless Cardiac Pacemaker as a Novel Intervention Modality for Atrioventricular Conduction Disturbance in Hypertrophic Cardiomyopathy

“…However, main components of current pacemakers are still the same of the first cardiac pacemaker type, such as a pulse generator and one or more transvenous leads. This design usually causes some shortterm and long-term complications (in approximately 10% of patients) [4,20]. The subcutaneous pocket is very prone to local infections and often causes skin erosion and hematoma inside the implantation region [20].…”

“…This design usually causes some shortterm and long-term complications (in approximately 10% of patients) [4,20]. The subcutaneous pocket is very prone to local infections and often causes skin erosion and hematoma inside the implantation region [20]. In addition, implantation procedures of this regular pacemaker also have several risks.…”

“…In the long-term, transvenous leads are associated with the majority of complications in regular pacemakers [19]. Those transvenous leads can potentially cause obstructions in the vena cava, and they are prone to insulation breaks, conductor fractures, lead dislodgements and even a systemic infection [3,20,21]. For these reasons, researchers now are developing a new design of pacemakers, which eliminates such leads.…”

“…On the one hand, Nanostim TM LCP uses a distal non-retractable single turn screw-in helix fixation unit as the primary fixation with three angled nitinol tines perpendicular to the helix as secondary fixations [3,22,24]. At the centre of the fixating helix, there is a steroid-eluting disc which acts as a tip electrode [20]. On the other hands, Micra TM TPS uses four self-expanding nitinol tines to attach to the myocardium with a steroid-eluting cathode in the distal part of the device [3,20].…”

“…At the centre of the fixating helix, there is a steroid-eluting disc which acts as a tip electrode [20]. On the other hands, Micra TM TPS uses four self-expanding nitinol tines to attach to the myocardium with a steroid-eluting cathode in the distal part of the device [3,20].…”