Micra implant a viable substitute to pacemakers

The Micra Transcatheter Pacing System (M-TPS) can be a safe and effective substitute to a conventional pacemaker, suggests a study presented at the recent EHRA 2023. M-TPS has a surgically created subcutaneous pocket and no transvenous leads, which help prevent complications.

“These devices are a reliable alternative after transvenous lead extraction (TLE), with similar electrical performances than those observed in patients who did not previously received pacing,” according to the researchers, led by Dr Pietro Paolo Tamborrino of Azienda Ospedaliero Universitaria Pisana in Pisa, Italy.

Tamborrino and his team conducted this research to assess the feasibility and long-term outcomes of M-TPS implant in patients who had TLE. They included those who received M-TPS implantation at their institution from May 2014 to September 2022. All patients met the standard criteria for pacemaker implantation (VVI or VDD mode).

Participants were categorized as either “naïve pacing” or “postextraction” patients. The researchers then scheduled follow-up at discharge, after 1 month, and every 6 months thereafter, as well as checked the electrical parameters.

Major complications were characterized by the following: life-threatening events, need for surgical intervention, or any event that causes significant haemodynamic instability or results in death.

A total of 193 patients (76.7 percent males) were included in the analysis, of which 57 (29.5 percent) underwent M-TPS implantation after TLE. The procedure was conducted due to infection in 91.4 percent of patients. [Tamborrino, et al, EHRA 2023]

Pacing was initiated due to several indications, including permanent atrial fibrillation with bradycardia in 107 (55.5 percent) patients, complete atrioventricular (AV) block in 59 (30.5 percent), symptomatic sinus node dysfunction in 20 (10 percent), and advanced AV block or bifascicular block in seven (4 percent).

No statistically significant between-group difference was noted in terms of demographics characteristics and primary pacemaker implant indications, except for mean age at implant, which was lower in the postextraction group (80 vs 78 years; p=0.04).

All patients had a successful implant procedure, and none of them experienced any major complications. In addition, no differences were observed in procedure duration (40 vs 45 min; p=0.34), fluoroscopy time (9 vs 9 min; p=0.31), and single device delivery (64.9 percent vs 67.9 percent; p=0.35) between groups.

Mean follow-up time was 12 months, with a maximum of 8 years.

No significant differences were noted in pacing variables at implantation (pacing threshold: 0.5 vs 0.5 V/0.24 ms; p=0.15; impedance: 720 vs 675 Ohm; p=0.51; R wave amplitude: 9 vs 8.2 mV; p=0.47), discharge (pacing threshold: 0.38 vs 0.38 V/0.24 ms; p=0.27; impedance: 685 vs 610 Ohm; p=0.16; R wave amplitude: 10.25 vs 9.3 mV; p=0.6), and at 6 months (pacing threshold: 0.5 vs 0.5 V/0.24 ms; p=0.64; impedance: 580 vs 570 Ohm; p=0.63; R wave amplitude: 11.9 vs 11.7 mV; p=0.68; battery voltage: 3.09 vs 3.09 V; p=0.71).

“The specific and well-known design features of … M-TPS have suggested [its] use in patients [who] previously underwent TLE for any reason,” the researchers said.