A novel stepwise catheter ablation method of the mitral isthmus for persistent atrial fibrillation: efficacy and reproducibility

Fig. 1. Endpoint of the mitral isthmus (MI) ablation. (A) Before ablation, the coronary sinus (CS) catheter recorded a CS1-2 to CS 9–10 activation sequence when pacing at the Left atrial appendage (LAA) by the Pentaray catheter (left). After ablation, the activation sequence was transformed into CS9-0 to CS1-2 (right); (B) Before ablation, the ablation catheter recorded a 1–2 to 3–4 activation sequence when pacing at the distal of the CS catheter (left). After ablation, the activation sequence was transformed into 3–4 to 1–2 (right)

Fig. 2. Ethanol infusion of the vein of Marshall (EI-VOM) and marked VOM ostium(red arrow)

Fig. 3. Endocardial “V-shape” linear ablation of the mitral isthmus (MI). The upper ablation line was closed to the root of the Left atrial appendage(LAA) from the 1–2 o’clock point of the mitral annulus at the Left anterior oblique (LAO) 45º view to the left inferior pulmonary vein(LIPV), closing to the root of LAA. The lower ablation line coursed from the LIPV to the lower MA anatomically corresponding to the ostium of the vein of Marshall (VOM)

Fig. 4. Activation mapping and reinforced ablation of the earliest activation sites (EASs). (A) The EASs around the upper line of the “V-shape” ablation were identified, and reinforced ablation was performed; (B) The EASs around the lower line were identified, and reinforced ablation was performed

Fig. 5. An earlier epicardial activation than the endocardium. activation sequence on CS1-2 (epicardium) was earlier than MAP1-2(endocardium) when ablating earliest activation sites (EASs).

Fig. 6. Precise epicardial ablation in the coronary sinus(CS). (A) The activation sequence was from distal to proximal CS catheter before epicardial ablation. (B) The activation sequence reversed after precise epicardial ablation pointing to the endocardial earliest activation sites (EASs) anatomically in CS.