Introduction: The “crosstalk” (CST) ablation technique has been reported to reduce unnecessary ablation during cryoballoon (CB) ablation (CBA). Nevertheless, it is unclear which situations will necessitate the adoption of the technique. Methods and Results: The effect of the technique was analyzed in AF patients underwent CBA from July 2017 to February 2020. The balloon occlusion status and nadir temperature (NT) were compared, and all ablated PVs were categorized into three groups according to the necessity and effectiveness of the technique. Of 1082 superior PVs (SPVs), 16, 40, and 1026 were identified in the CST success group, CST failure group, and control group, respectively. The proportion of SPVs ablated with complete occlusion with CB was significantly higher in the CST success group (100%) than in the CST failure group (16.7%) or control group (49.4%) (CST success group vs. CST failure group, p<0.001; CST success group vs. control group, p<0.002). The proportion of SPVs ablated with NT ≤-46°C was higher in the CST success group (100%) than in the CST failure group (56.7%) (p<0.05). The CST ablation technique was always effective if CBA of the SPVs was performed with both complete occlusion and NT ≤-46°C and was almost always ineffective if it did not meet these two criteria (sensitivity, 100%; specificity, 93%). Conclusion: Successful CST ablation was highly predicted if complete PV occlusion and NT ≤-46°C during CBA of the SPVs were achieved, which could be useful when adopting the technique targeting inferior PVs to reduce unnecessary freezing during SPV isolation.

Objective: To investigate the incidence, risk factors and clinical characteristics of periaortic VTs after AVR. Background: The periaortic region is the origin of some ventricular tachycardias (VTs) after aortic valve replacement (AVR). However, the clinical characteristics of periaortic VTs after AVR are yet to be clarified. Methods: We retrospectively analyzed clinical courses of 109 patients who had undergone surgical AVR (SAVR) without other structural heart diseases between April 2009 and Jun 2019 and evaluated the incidence and characteristics of periaortic VTs after SAVR. Results: Three patients (2.8%) developed periaortic VTs after SAVR. The average duration of onset was 12.3±6.6 years. All VTs arose from the inferior axis; they included both left and right bundle branch block configuration (LBBB and RBBB). Two patients underwent cardiac magnetic resonance imaging; late gadolinium enhancement (LGE) was observed in the mid-layer of the left ventricle basal anteroseptal wall in both cases. Patients with periaortic VTs had significantly wider interventricular septum, lower left ventricular ejection fraction (LVEF), larger LV diameter at systole, and higher positive rates of signal-averaged ECG and non-sustained VTs on Holter. On ablation, local fragmented potentials with low voltage zones were observed in accordance with the distribution of LGE. Multiple VTs originating from the periaortic region were provoked in the sessions. Conclusions: Periaortic VTs long after surgical AVR are not rare, and arrhythmia risk stratification, including that by signal averaged electrocardiogram (SAECG), Holter, and cardiac magnetic resonance imaging (MRI) should be considered.