Home > Electrophysiology > Journal Club 23 September 2015

Journal Club 23 September 2015


Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker





Cardiac pacemakers are limited by device-related complications, notably infection
and problems related to pacemaker leads. We studied a miniaturized, fully selfcontained
leadless pacemaker that is nonsurgically implanted in the right ventricle
with the use of a catheter.


In this multicenter study, we implanted an active-fixation leadless cardiac pacemaker
in patients who required permanent single-chamber ventricular pacing. The primary
efficacy end point was both an acceptable pacing threshold (≤2.0 V at 0.4 msec)
and an acceptable sensing amplitude (R wave ≥5.0 mV, or a value equal to or
greater than the value at implantation) through 6 months. The primary safety end
point was freedom from device-related serious adverse events through 6 months.
In this ongoing study, the prespecified analysis of the primary end points was
performed on data from the first 300 patients who completed 6 months of followup
(primary cohort). The rates of the efficacy end point and safety end point were
compared with performance goals (based on historical data) of 85% and 86%,
respectively. Additional outcomes were assessed in all 526 patients who were enrolled
as of June 2015 (the total cohort).


The leadless pacemaker was successfully implanted in 504 of the 526 patients in
the total cohort (95.8%). The intention-to-treat primary efficacy end point was met
in 270 of the 300 patients in the primary cohort (90.0%; 95% confidence interval
[CI], 86.0 to 93.2, P = 0.007), and the primary safety end point was met in 280 of
the 300 patients (93.3%; 95% CI, 89.9 to 95.9; P<0.001). At 6 months, device-related
serious adverse events were observed in 6.7% of the patients; events included device
dislodgement with percutaneous retrieval (in 1.7%), cardiac perforation (in 1.3%),
and pacing-threshold elevation requiring percutaneous retrieval and device replacement
(in 1.3%).


The leadless cardiac pacemaker met prespecified pacing and sensing requirements
in the large majority of patients. Device-related serious adverse events occurred in approximately
1 in 15 patients.

Supplementary Material

Supplementary material is available here.

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