Impact of PREVENTIVE Substrate Ablation of Coronary Chronic Total Occlusion on Implantable cardioVerTer-Defibrillator Interventions
Condition: Ventricular Tachycardia; Ischemic Cardiomyopathy
MeSH terms: Cardiomyopathies; Tachycardia; Tachycardia, Ventricular; Ischemia
Study type: Interventional

Summary: 
      The aim of this study is to assess whether preventive substrate ablation of chronic total
      occlusion infarct-related artery (CTO-IRA) area in heart failure (HF) patients correlates
      with lower appropriate implantable cardiac defibrillator (ICD) therapies. In addition, the
      purpose of the study is to determine whether prophylactic substrate ablation at the time of
      primary ICD implantation in high-risk ischemic patients affects unplanned hospitalization, HF
      progression, and quality of life.
    

Detailed description: 
      Implantable cardioverter-defibrillators (ICDs) improve survival among patients with ischemic
      heart failure (HF) who have not previously had a sustained ventricular arrhythmia. However,
      ICD shocks that terminate ventricular tachycardia (VT) are associated with higher mortality,
      which may be a reflection of ICD shocks being a marker of more advanced disease versus shocks
      causing a worse prognosis. In addition, ICD shocks are associated with decreased functional
      status and quality of life. Antiarrhythmic medications (AAD) reduce ICD shocks but have high
      rates of side effects and lack of compliance within 1 year of initiation. Some randomized,
      controlled clinical trials have shown that catheter ablation (CA) of VT can decrease the
      number of episodes of VT and ICD shocks which could translate to an improvement in patient
      outcomes.

      Regarding the approach to CA of VT, several controversies and gaps of knowledge can be found
      in the literature. Some authors target predominantly "clinical VTs" (activation and
      entrainment mapping), while others focus on the substrate causing VTs without focusing on VT
      morphologies (elimination of local abnormal ventricular activities and late potentials). In
      addition, data on timing of the CA procedure is inconsistent. However, early CA strategy
      seems feasible as end-stage cardiovascular disease increases procedural risk and is
      associated with arrhythmias that may be less amenable to successful treatment with ablation.

      The current focus on risk stratifying patients with ischemic cardiomyopathy who could benefit
      from a primary prevention ICD solely on basis of ejection fraction and NYHA class is far from
      ideal. In patients with ischemic HF, the presence of the coronary chronic total occlusion
      (CTO) is related to worse long-term prognosis. Moreover, in a subgroup of ischemic patients,
      CTO associated with a previous infarction in its territory was an independent predictor of
      ventricular arrhythmias. Recent studies reported that primary prevention patients with CTO of
      an infarct-related artery (CTO-IRA) have a very high risk of appropriate ICD therapies due to
      fast VTs. As post-myocardial infarction scar is a well-recognized substrate of VTs, these
      patients might benefit from prophylactic substrate ablation at the time of primary ICD
      implantation.

      Eligible and consenting patients on optimal medical HF treatment with confirmed CTO-IRA will
      be equally randomized to receive either a primary prevention ICD or a CA procedure and an
      ICD. Catheter ablation with a uniform procedural endpoint and definition of acute procedural
      success was to be performed before ICD implantation. ICD programming will be standardized for
      all subjects according to primary prevention settings.

      Subjects will be seen at baseline randomization, then 1 month after ICD implantation and
      every 6 months thereafter until the end of the study. Subjects will be followed up for a
      minimum of 24 months. Quality of life questionnaires will be done at each visit.

      The aim of this study is to assess whether preventive substrate ablation of CTO-IRA area in
      HF patients correlates with lower appropriate ICD therapies. In addition, the purpose of the
      study is to determine whether prophylactic substrate ablation at the time of primary ICD
      implantation in high-risk ischemic patients affects unplanned hospitalization, HF
      progression, and quality of life.
    

Intervention name(s): Catheter ablation of ventricular tachycardia; Optimal medical treatment
Intervention type(s): Procedure; Drug
Intervention description(s): Catheter ablation with a uniform mapping system, procedural endpoint, and definition of acute procedural success.; Optimal guidelines-based heart failure treatment and antiarrhythmic drugs. Antiarrhythmics will be avoided if possible in the ablation group.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Ventricular Tachycardia; Ischemic Cardiomyopathy; Primary prevention; Heart Failure