Implantation site
During implantation, the implanter intended to deploy
MicraTM pacemaker in the mid-septum based on the
fluoroscopic RAO 30 image. Postoperative 3D reconstructive CT image of
the heart was completed in all patients in both groups and the position
of the MicraTM pacemaker in the ventricular septum was
determined. Figure 2A-C show an example of MicraTMpacemaker deployment in the mid-septum in zone 2 at implantation and
confirmed in the post-implantation CT scan. Post-operative CT
reconstructed image confirmed the MicraTM pacemaker
location in septal zone 2 (mid-septum) in 13 cases in the
non-radiography group (48.1%, 13/27) and 76 cases in the radiography
group (93.8%, 76/81, Figure 2D). The difference in the accuracy of
intended deployment sites between two groups was significant
(P < 0.0001). Other locations confirmed by CT-scan image
included the superior and inferior septum as shown in Figure 3. In the
non-radiography group, MicraTM pacemaker was deployed
in the inferior septum in 6 patients (22.2%) and the superior septum in
8 patients (29.6%) while in the radiography group,
MicraTM pacemaker was deployed in the inferior septum
in 2 patients (2.5%) and the superior septum in 3 patients (3.7%). In
comparison with fluoroscopic image, the site in the superior septum
identified in the CT image was found in zone 1 of the fluoroscopic
nine-partition image while the site in the inferior septum in CT image
was found in zone 3 that was close to the right ventricular apex.