METHODS
We conducted the differential diagnoses including CRT, His bundle
pacing, and left bundle branch pacing. In order to obtain exact
diagnosis, we arranged this patient a bedside chest X-ray. From the
chest X-ray, we failed to find relevant pacing electrode placed in the
field of left ventricle, His bundle and left bundle branch. The
pacemaker on the right side is a 15-year-old single-chamber pacemaker,
with its electrode lead located at the right ventricular apex(Figure
4a). The pacemaker on the left side is a one-week-old dual-chamber
pacemaker with pacing electrodes situated in the right atrial appendage
and the proximal septum (Figure 4a).
Moreover, three spike signals are observed during stable pacing periods,
with fixed spikes occurring during in AV delay at 180 ms intervals,
excluding other operation types such as CRT and His bundle pacing.