CatHeter Ablation of perSistEnd Atrial Fibrillation: Pulmonary Vein Isolation Versus Defragmentation. The CHASE-AF Study
Condition: Atrial Fibrillation; Persistent Atrial Fibrillation
MeSH terms: Atrial Fibrillation
Study type: Interventional

Summary: 
      Study design:

      Randomized prospective comparison of pulmonary vein isolation alone versus a strategy aiming
      for atrial fibrillation termination by using a stepwise approach consisting of pulmonary vein
      isolation, biatrial defragmentation aiming for fractionated electrograms and linear ablation
      if required.
    

Detailed description: 
      Study protocol:

      In patients randomized to PVI alone, the index procedure consists of wide circumferential
      pulmonary vein isolation (1 cm distal of the PV ostium) including optional right atrial
      isthmus ablation. Endpoint for PVI is entrance block as evaluated by a circumferential
      mapping catheter during sinus rhythm at the end of the procedure. In all patients the NavX®
      three-dimensional mapping system should be used. The St. Jude Medical Coolflex® or Coolpath®
      catheters may be used at the operator's discretion.

      In patients randomized to the strategy aiming for atrial fibrillation termination PVI is also
      the initial step of the procedure followed by atrial defragmentation and eventual linear
      ablation in case of atrial tachycardia aiming for acute restoration of sinus rhythm. The
      procedural steps with regard to mapping and ablation of atrial fibrillation and consecutive
      atrial tachycardia follow the previously described methods (8,9). After initial ablation the
      previous antiarrhythmic drug treatment can be continued but no de novo antiarrhythmic drug
      regiment should be applied. The primary endpoint of this study is recurrence of atrial
      arrhythmias between 6 and 12 months after the initial ablation procedure.

      In both study arms, the same CE certified catheters will be used. Usually, the setting
      consists of on decapolar catheter positioned in the coronary sinus, one circumferential
      mapping catheters for mapping of the pulmonary veins, one quadripolar catheter for mapping
      the right atrium. In both study groups a externally irrigated catheter for mapping and
      ablation will be used (CoolFlex/ Coolpath as mentioned above).

      Sample size calculation:

      According to the assumption of a difference of 30 % regarding the primary endpoint (power 80,
      alpha=0.05) 70 patients have to be included. Considering a potential drop out of 10 % 160
      patients should be included. However, an adaptive statistical plan is applied (Prof.
      Wegscheider, University Hospital Hamburg).

      Follow up and repeat procedures:

      Crossover between the two treatment options should be avoided. Previous antiarrhythmic drug
      treatment can be continued until month 6 after the index procedure is completed. Repeat
      procedures between month 0 and 3 should be avoided. Repeat procedures should be planned
      between month 3 and 6 after the index procedure. The initial approach of the repeat procedure
      is the same as during the index procedure (Figure 1). Thus, in patients randomized for PVI
      alone, PVI will be repeated in case of reconnection of the veins. In the setting of complete
      block of all pulmonary veins also patients randomized to PVI alone will receive a substrate
      modification as in the other group. Patients randomized to the ablation procedure aiming for
      AF termination will again receive a 'complete' procedure including assessment of PVI and
      ablation of atrial tachycardias and atrial fibrillation.

      Follow-up:

      All patients will be seen in the outpatient clinic every 3 month during the 12 month study
      period. The visit will include ECG and Holter ECG recordings. Additionally, echocardiography
      and interrogation of pacemaker will be performed.
    

Intervention name(s): PVI alone; PVI + Defragmentation + linear lesions
Intervention type(s): Procedure; Procedure
Intervention description(s): PVI alone Pulmonary vein isolation alone in persistent atrial fibrillation; PVI + Defragmentation + linear lesions AF ablation continuation aiming for AF termination
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment