A totally self-contained, lead-less pacemaker (Nanostim, Pacesetter, Inc./St. Jude Medical, USA) has been shown to be safe and effective in 33 patients with an indication for single (right) ventricle pacing. It is a lead-less cardiac pacemakers experimental and investigational for arrhythmia and all other indications because of insufficient evidence of its safety and effectiveness.
Lead-less pacemakers are designed to achieve the same pacing results as a standard pacemaker, but the process for implanting the lead-less pacemaker is different from standard pacemakers. The lead-less pacemaker is placed via a catheter into the right ventricle. Unlike a standard pacemaker, a lead-less pacemaker does not require creation of a surgical pocket for the pacemaker, and it requires no leads. The pacemaker battery life is equivalent to that of similar standard single chamber pacemakers.
The primary safety end point was freedom from complications at 90 days. Secondary performance end points included implant success rate, implant time, and measures of device performance (pacing/sensing thresholds and rate-responsive performance). The mean age of the patient cohort (n=33) was 77±8 years, and 67% of the patients were male (n=22/33). The most common indication for cardiac pacing was permanent atrial fibrillation with auriculoventricular block (n=22, 67%). The implant success rate was 97% (n=32). Five patients (15%) required the use of >1 lead-less cardiac pacemaker during the procedure. One patient developed right ventricular perforation and cardiac tamponage during the implant procedure, and eventually died as the result of a stroke. The overall complication-free rate was 94% (31/33). After 3 months of follow-up, the measures of pacing performance (sensing, impedance, and pacing threshold) either improved or were stable within the accepted range.
Acknowledgement: The speaking panel acknowledge Radcliffe Cardiology for providing writing and editorial support.
A lead-less cardiac pacemaker system is a pulse generator with built-in battery and electrode for implantation in a cardiac chamber via a transferal catheter approach.
Additional studies are necessary to evaluate the safety, efficacy and stability of lead-less pacemakers.