Incidence and distribution of abnormal conduction zone
Figure 3 shows the incidence and distribution of the ACZ in each LA region. Of the 100 patients, the ACZ was most frequently observed in the anterior wall region (77%). Moreover, a tendency of increased ACZ in the anterior wall region was shown in the other categories (PAF, non-PAF, normal/mildly enlarged LA, moderately enlarged LA, and severely enlarged LA). Compared to the PAF group, the incidence of the ACZ was higher in the non-PAF group in global LA (100% vs 90%, P=0.0245), anterior (86% vs 69%, P=0.0424), posterior (20% vs 4%, P=0.0112), and roof (59% vs 31%, P=0.0052). A larger LA size was significantly associated with a higher incidence of a ACZ in anterior, posterior, inferior, and roof (Figure 3 ). Figure 4shows the incidence of the ACZ and LVA in each group. In the 100 patients, the ACZ (95%) had a significantly higher incidence rate than for each LVA (mild LVA: 78%, moderate LVA: 56%, severe LVA: 20%). Furthermore, these tendencies were also observed in the other groups (Figure 4 ).