Miniature leadless pacemaker shows low complication rate at more than 7 months

At follow-up of more than 7 months, a miniaturized leadless pacemaker was associated with a lower complication rate compared with transvenous pacemakers, according to findings presented at Cardiostim–EHRA Europace 2016.

The leadless transcatheter pacing system (Micra, Medtronic), one-tenth the size of a traditional pacemaker, is connected to the heart with tines and paces the heart through an electrode at the device’s end. Because it does not use leads or a surgical pocket, the risk for complications is greatly reduced, according to the study background.

"Clinicians are extremely pleased that the evidence continues to demonstrate the strong safety profile of the Micra for all patient groups," presenter Gabor Z. Duray, MD, PhD, head of clinical electrophysiology and pacing at the State Health Center in Budapest, Hungary, said in a press release issued by Medtronic. "These data provide the largest sample and the longest follow-up reported for this technology to date. We look forward to further evaluating this minimally invasive, leadless option in patients across the world."

The cohort of 726 patients implanted with the leadless pacemaker were followed for an average of 7.7 months, and major complication rates were compared with a historical control group of patients with transvenous pacemakers. Electrical performance was characterized up to 12 months after implantation.

At 7.7 months, the rate of major complications in those receiving a leadless pacemaker was 3.7%, with no dislodgements or infections, Duray said. There were only two new events, one cardiac failure and one case of pacemaker syndrome, since 6-month results were reported in November.

According to the researchers, compared with the historical control group of patients with transvenous pacemakers at 7.7 months, patients with the leadless pacemaker had 52% fewer major complications (HR = 0.48; 95% CI, 0.32-0.72). The result was consistent across all subgroups.

Low and stable pacing thresholds remained in 98.3% of patients in the leadless pacemaker cohort at 6 months (implant, 0.63 V at 0.24 ms; 6 months, 0.59 V at 0.24 ms), and the estimate of battery life based on 6-month data is 12.2 years, according to the researchers.

The device received FDA approval in April and can be used with 1.5-Tesla and 3-T full-body MRI scans, according to the release. – by Dave Quaile

Reference:

Duray G, et al. Late-Breaking Devices. Presented at: Cardiostim–EHRA Europace 2016; June 8-11, 2016; Nice, France.

Disclosure: Duray reports financial ties with Biotronik, Boston Scientific, Johnson & Johnson, Medtronic and St. Jude Medical.