Leadless Atrial Pacemaker Implantation at a Nonstandard Site After Unsuccessful Conventional Atrial Placement

FIGURE 1. Unsuccessful implantation at the conventional right atrial appendage site. (A) Fluoroscopic image demonstrating the positioning and screw fixation of the atrial leadless pacemaker at a conventional right atrial appendage (RAA) site. (B) Commanded atrial electrograms recorded before and after screw fixation. The current‐of‐injury amplitudes were 1.0 mV before fixation and 1.5 mV after fixation. Atrial capture was absent at 6.0 V/0.4 ms both before and after fixation. Despite screw fixation and approximately 15 min of observation, atrial capture remained absent at 6.0 V/0.4 ms.

FIGURE 2. Commanded atrial electrograms during systematic premapping. Representative commanded atrial electrograms (cEGMs) recorded at atrial sites where capture was observed during premapping at 3.0 V/0.4 ms. These sites were assessed without screw fixation.

FIGURE 3. Final implantation at the high right atrial septum. (A) Fluoroscopic images demonstrating the positioning of the atrial leadless pacemaker at the high right atrial septum. (B) Commanded atrial electrograms recorded before and after screw fixation at the final implantation site. The current‐of‐injury amplitude was 2.0 mV both before and after fixation. The pacing threshold was 3.5 V/0.4 ms before fixation and 2.25 V/0.4 ms after fixation. (C) Cardiac computed tomography and three‐dimensional reconstruction demonstrating the anatomical location of the atrial leadless pacemaker at the high right atrial septum and its relationship to the superior vena cava, right atrial roof, and right atrial appendage region.