At present, the patient was admitted to our hospital due to frequent ICD
shocks. His ICD record showed rapid monomorphic VT (mean cycle length,
185 ms), which was always triggered by the same premature ventricular
contraction (PVC) (Figure 2). The morphology of the PVC was a left
bundle branch block configuration with an inferior axis, and catheter
ablation to the trigger PVC was performed. A three-dimensional (3D)
voltage map of the right ventricle was constructed, and a low-voltage
area (LVA) on the free wall of the right ventricular outflow tract
(RVOT) was detected. A good pacemap was obtained at the border zone of
the LVA, and the target PVC was ablated at the site. Shortly after
discharge, he experienced the recurrence of ICD shocks and underwent a
second ablation session the following month. However, the ablation
failed again, and he revisited our hospital a month after the second
session due to frequent ICD shocks. Monomorphic VT originating from the
RVOT was recorded on an electrocardiogram (Figure 3A), and the third
ablation session for recurrent VT was performed. The morphology of the
VT was the same as the trigger PVC, which was frequently observed during
his sessions. An almost perfect pacemap (score, 96) with PVC was
obtained near the LVA, slightly posterior to the prior ablation site.
The ventricular potential of the PVC on the ablation catheter showed up
earlier than the QRS onset of any leads on the electrocardiogram at this
site (Figure 3B–C). Both VT and PVC were successfully eliminated and
not inducible after ablation. There were no ICD shocks one year after
the last session.