The first-in-human trial of a new miniaturized leadless pacemaker implanted directly inside the heart found that the transcatheter pacing system (TPS) can be safely and effectively applied in patients with a slow heart rhythm. Early performance results from the international Micra Transcatheter Pacing Study were presented today at Heart Rhythm 2015, the Heart Rhythm Society’s 36th Annual Scientific Sessions.
Permanent cardiac pacing is the only effective treatment for symptomatic bradycardia, or a slow heart rhythm. Patients can experience complications mostly related to the pacing leads and chest pocket. The new miniaturized pacemaker is 93 percent smaller and reduces complication risks compared to conventional transvenous pacing systems because it does not use leads or require a chest pocket. Instead, the device is implanted from the femoral vein and fixated directly in the right ventricle of the heart using protractible nitinol tines.
The Micra Transcatheter Pacing Study enrolled 140 patients with a wide variety of profiles from 37 implanting physicians from 23 countries. This interim analysis examined the first 60 patients to undergo implantation of TPS and receive three months of follow-up. The study examined serious adverse events related to TPS, 24 hour ambulatory electrocardiograms and device function. Electrical variables were measured at implant, pre-hospital discharge and after one and three months.
All implant attempts were successful with an average implant time of 37 minutes, and all electrical measurements were within expected ranges at one and three months. A total of 5.7 percent of patients experienced serious adverse events, which is comparable to traditional systems and there were no procedural-related deaths. The estimated device longevity based on observed mean pacing percentages is approximately 10 years, which is similar to traditional devices. Examination of 24 hour ambulatory surface ECG and device electrogram indicated expected pacing and sensing performance with no pauses due to inappropriate TPS operation.
“The results of this study are very promising and we have seen firsthand how the device size and minimally invasive procedure truly can improve the quality of life for patients,” said lead author Philippe Ritter, MD from the Hôpital Haut-Lévêque in Bordeaux, France. “The new miniaturized pacemaker not only eliminates many of the traditional complications associated with conventional transvenous pacing, but it also has the potential to advance patient care and set a new standard for single chamber pacemakers.”
The long-term safety and benefits of TPS will be further evaluated in this trial.