Severe Complications During Ventricular Tachycardia or Premature Ventricular Complex Ablation

Inclusion Criteria:

* Centers : Centers participating in the present collaborative study group. Invitation to participate will be based either upon personal referral of one of the investigator, previous collaboration or based on a meta-analytic review of the literature published on the subject within the past 20 years.
* Patients: Females and males of \>18 years undergoing any type of VT/PVC ablation. While we will accept redo-procedure we will ask for a unique patient-identifier to link procedures belonging to the same patients together.
* Interventions: VT/PVC ablation (first intervention or re-do) as routinely performed by the participating centers
* Outcomes: Severe complications, defined as hemodynamic instability requiring mechanical intensive-care management, tamponade, stroke, cardiac arrest, myocardial infarction, phrenic nerve palsies, major bleeding requiring transfusion, vascular or cardiac complication requiring surgery, procedure-related death.
* Setting: Observational cohort studies, registries, retrospective cohort studies. Data stemming from RCTs (Randomized controlled trials) will not be collected as they likely do not represent a "real-life" setting.
* Length of follow-up: Peri-procedural complications
* Years considered: Not limited to a specific time-frame, but to reflect common ablation practices, we will focus on data from the 20 past years.
* Number of patients provided : No lower limit of patients provided per dataset or ablation volume per year to include high- as well as low-volume centers

Exclusion Criteria:

* Refusal of the center to participate.
* Less than 10 procedures available in the dataset (no case reports)
* Missing essential baseline characteristics, missing collection of sufficient details regarding each complication.