Rate‐dependent and unidirectional conduction block between the left pulmonary vein and left atrium after catheter ablation for atrial fibrillation

FIGURE 1. (A) Sinus rhythm shows conduction to the LPV (red arrow). (B) Pacing from the LPV at a pacing cycle length of 320 ms captured local myocardium (red broken arrow) without conducting to the LA (blue arrow) and LAA (green arrow). (C) PV‐LA conduction was revealed when pacing cycle length was shortened to 300 ms. This pacing captured the myocardium of the LSPV (red broken arrow) and was conducted to the LA (blue arrow) and LAA (green broken arrow). LPV, left pulmonary vein; LA, left atrium; LAA, left atrial appendage

FIGURE 2. PAC with the same atrial sequence was observed repeatedly (black arrow). Note that the atrial sequence of this PAC was the same as the atrial sequence observed during the pacing of LSPV. Under isoproterenol loading, firing of the LPV under sinus rhythm occurred repeatedly following this PAC (blue asterisk), and this PAC also appeared during this PV firing. After the PAC under PV firing, atrial firing was also observed (red asterisk). LPV, left pulmonary vein; LA, left atrium; PAC, premature atrial contraction

FIGURE 3. (A) Gap 1 was assumed to exist in the anterior of the carina of the LPV and show LA‐LPV unidirectional conduction. Gap 2 was assumed to exist in the roof of the LSPV and show LPV‐LA unidirectional conduction. Gap 2 was also assumed to have rate‐dependent conduction. (B) Ablation was performed for Gap 1 identified in the anterior carina of the LPV. After ablation of Gap 1, unidirectional LA‐LPV conduction was eliminated (C) Three‐dimensional (3D) electroanatomic activation mapping of LA by CARTO was performed during pacing of the LPV with a cycle length of 260 ms. Gap 2 was revealed as the earliest site of LA activation and was detected in the roof of the LPV (red arrow). Visitags are displayed on the ablation site of Gap 2. The electrogram shows the earliest activation site of the LA in the ablation catheter detected by CARTO mapping during LSPV pacing. This precedes the earliest activation site of the catheter deployed at CS and HRA by 63 ms. (D) Radioscopic image of ablation of Gap 2. After ablation of Gap 2, rate‐dependent LPV‐LA conduction disappears. LPV, left pulmonary vein; LA, left atrium