In a contemporary cohort of patients with scar-related VT undergoing RFCA, EM occurred in 5% of cases. Clinical and procedural variables indicating poorer clinical status (low LVEF, chronic kidney disease, VT storm, and unmappable VTs) and post-procedural VT recurrence may predict EM. Identification of such features may prompt early consideration for hemodynamic support or other care to help mitigate later potential complications.

Patients with ES have a high risk of VT recurrence and mortality. Patient and procedure characteristics are consistent with advanced cardiac disease and longer and more complex procedures. In patients with ES, acute procedural success is associated with a significant reduction in VT recurrence and improved 1-year survival.

Background: Several distinct risk factors for arrhythmia recurrence and mortality following Ventricular Tachycardia (VT) ablation have been described. The effect of concurrent risk factors has not been assessed so far, thus it is not yet possible to estimate these risks for a patient with several comorbidities. Aim of the study was to identify specific risk groups for mortality and VT recurrence using the Survival Tree analysis method. Methods: In 1251 patients 16 demographic, clinical and procedure-related variables were evaluated as potential prognostic factors using Survival Tree (ST) analysis employing a recursive partitioning algorithm that searches for relationships among variables. Survival time and time to VT recurrence in groups derived from ST analysis were compared by a log-rank test. A random forest analysis was then run to extract a variable importance index and internally validate the ST models. Results: LVEF, ICD/CRT device, previous ablation (Previous Abl) were, in hierarchical order, identified by ST analysis as best predictors of VT recurrence, while LVEF, previous Abl, Electrical Storm (ES) were identified as best predictors of mortality. Three groups with significantly different survival rates were identified. Within the HIGH risk group, 65.0% patients survived and 52.1% were free from VT recurrence; within MEDIUM and LOW risk groups, 84.0% and 97.2% patients survived, 72.4% and 88.4% were free from VT recurrence, respectively. Conclusions: Our study is the first to derive and validate a decisional model that provides estimates of VT recurrence and mortality with an effective classification tree. Pre-procedure risk stratification could help optimize peri- and post-procedural care.