PMC9874696_01
Twelve lead-ECG recorded before the procedure showing sinus rhythm, PVC-1, and PVC-2. ECG, electrocardiogram; PVC, premature ventricular contraction.
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However, a serious of ECGs show frequent bi-morphic PVCs characterized by left bundle branch block (LBBB) and/or right bundle branch block (RBBB) in Figure 1, whose QRS wave were upright in leads II, III, and aVF (an inferior axis).
Activation mapping of PVCs. (A) Intracardiac ECG (left panel) and electro-anatomic map (right panel) obtained during activation mapping of PVC-1 in the anterior septum of RVOT. (B) Intracardiac ECG (left panel) and electro-anatomic map (right panel) obtained during activation mapping of PVC-2 near the LCC. (C) Intracardiac ECG (left panel) and electro-anatomic map (right panel) obtained during activation mapping of PVC-1 at the L-RCC. The bipolar ECG exhibited the LVP preceding the QRS onset, and electro-anatomic map showed ablation site in different electro-anatomic mapping areas. ECG, electrocardiogram; LCC, left coronary cusp; L-RCC, the left-right coronary cusp commissure; LVP, local voltage potential; MAP1, unipolar ECG; MAP1-2, bipolar ECG; RCC, right coronary cusp; PVC, premature ventricular contraction; RVOT, right ventricular outflow tract.
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RVOT (Figure 2A). Radiofrequency ablations (35 W, 17 ml/min, 2 min, 45 C) in this location reduced the occurrence of PVC-1, but the onset of PVC-2 shortly became frequent. The site of earliest activation (-41 ms before the onset of the surface QRS), was identified near the left coronary cusp (LCC) (Figure 2B). The L-RCC was focused (-44 ms before the onset of the surface QRS) and PVC elimination was achieved after ablation in this location (Figure 2C).