Figure 1. Cabrera Sequence Recording
The above pacing ECG shows sequential capture of the atrium and
ventricle, with dominant spikes at the beginning of the P wave and an
aberrant QRS complex, maintaining a basic cycle of 1000 ms. The ECG
reveals right atrial appendage pacing with a positive P wave in leads I,
II, III, and aVF, a negative P wave in lead aVR, and a biphasic P wave
in lead V1, with a PtfV1 of 0.05 mm/s. The ventricular electrode is
positioned in the right ventricular outflow tract, indicated by a left
bundle branch morphology in lead V1, a QS complex in leads I and aVL,
and a tall R wave in leads II, III, and aVF. Additionally, 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. Upon encountering
this ECG, a pacemaker interrogation was performed immediately.
ECG, electrocardiogram; AV, atrioventricular; CRT, cardiac
resynchronization therapy