Influence of different RR-NSVT patterns on VTAs occurrence
The influence of different RR-NSVT patterns on subsequent VTA occurrence was analyzed within the RR-NSVT (+) group. Table 4 shows the adjusted hazard ratio of various RR-NSVT patterns. Frequent, cluster RR-NSVT, and polymorphic RR-NSVTs were examined as the covariates possibly associated with VTA occurrence. Frequent RR-NSVT (HR: 2.503; 95% CI: 1.317-4.757; p=0.005) presented a positive association with VTA occurrence and cluster RR-NSVT (HR: 1.810; 95% CI: 0.984-3.329; p=0.056) presented a non-significant trend of association with VTA occurrence (Table 5). Polymorphic RR-NSVT showed no significant association with VTA occurrence. The time interval (median) from the first occurrence of frequent and cluster RR-NSVTs until the subsequent VTA event were 0 (0-1) and 105 (62-119) days, respectively. Most patients [57.1% (12/21)] experienced frequent RR-NSVT and subsequent VTAs on the same day. A Kaplan-Meier curve of VTA occurrence showed a significant difference among patients without RR-NSVT and those with RR-NSVT with or without cluster pattern (p<0.001) (Figure 4). Event-free survival was better in the RR-NSVT (-) group compared with the cluster RR-NSVT (-) group (p<0.001). Between the cluster RR-NSVT (-) and cluster RR-NSVT (+) groups, the log-rank p-value of the Kaplan-Meier curve was 0.050.