Randomized Trial of Two Different Strategies to Treat Paroxysmal Atrial Fibrillation
Condition: Atrial Fibrillation
MeSH terms: Atrial Fibrillation
Study type: Interventional

Summary: 
      The purpose of this study is to investigate the significance of complete versus incomplete
      electrical isolation of pulmonary veins by radiofrequency-induced linear lesions in patients
      with paroxysmal atrial fibrillation.

      The study hypothesis ist that the complete linear PV isolation ablation is superior to the
      non-complete linear PV isolation on the outcome of patients with idiopathic drug-refractory
      atrial fibrillation. As a second hypothesis in this adaptive study design, the
      non-inferiority of the complete linear PV isolation strategy will be tested.
    

Detailed description: 
      Atrial fibrillation can be cured by elimination of triggering events such as atrial
      extrasystoles originating from the pulmonary veins (PV) by selective or linear radiofrequency
      current applications.

      Although electrical isolation can be demonstrated by a circumferential mapping catheter
      positioned at the PV ostium, longterm effect of such EP-guided PV isolation procedures
      achieve about 60-70% of stable sinus rhythm during follow-up even in experienced centers.
      Re-investigation of symptomatic patients after initially electrically isolated PVs
      demonstrated a substantial amount of PV reconduction which might explain the arrhythmia
      recurrence.

      Although it was demonstrated that linear lesions for PV isolation is superior to the
      selective ablation approach, conflicting data exists on the necessity to achieve complete
      linear lesions. The groups of Pappone et al and Oral et al both published a success rate of
      more than 90% of patients in sinusrhythm irrespective of the line completeness, which both
      groups estimated to be reached in only 30% of cases.

      Several advantages and disadvantages could advocate for either the complete versus the
      incomplete ablation strategy: Performing the complete EP-guided linear PV isolation strategy
      might take longer (mean duration 4.5 hours vs about 2 hours) and could thereby potentially
      result in a higher risk of procedure-associated complications (air embolism, thrombus
      formation, perforation). In addition, three transseptal sheaths might increase the risk of
      tamponade and might aggravate the ability to safely navigate catheters in the left atrium.
      Certainly, the procedure costs are higher, since in addition to the 3D mapping system two
      circular mapping catheters are mandatory to facilitate the lesion deployment and avoidance of
      intra-PV ablation.

      In addition, an ablation strategy that does not depend on complete line deployment may be
      sufficient to achieve stable sinus rhythm. Although, additional linear lesions between the PV
      isolation segments and towards the mitral annulus as proposed by several centers with
      incomplete linear PV isolation approaches might not be necessary to achieve stable sinus
      rhythm. Potential complications such as atrio-esophageal fistula formation could be avoided
      if no additional lesions eg. along the LA roof would be necessary. Both the costs of the
      additional material (transseptal sheaths, circular mapping catheters) and the shorter
      procedure duration (about 2 hours) would be reduced. On the other hand, these costs would be
      balanced by the reduced number of re-ablation, if incomplete PV isolation would indeed lead
      to a higher AF recurrence rate.

      Since no data exist on the time course of the deployed ablation lines. Do patients with
      recurrences of AF always have PV reconduction ? Vice versa, it also remains unclear if all
      patients with stable sinus rhythm do experience this effect based on longterm PV isolation.
      To assess the significance of the time course of PV isolation, the proposed study protocol
      consists therefore of an invasive re-evaluation of all primarily ablated pts scheduled after
      3 months of follow-up regardless of arrhythmia recurrence to investigate PV conduction
      properties.

      Finally, patients with symptomatic AF who underwent intensified ECG monitoring indicate that
      the standard clinical procedures (assessment of symptoms and surface ECG recordings at long
      intervals) are not sufficient to detect recurrent AF. Therefore, daily ECG monitoring is
      planned in this trial to detect asymptomatic episodes of AF.

      The proposed study protocol aims to investigate in prospective, randomized fashion the
      significance of complete versus incomplete PV isolation by RFC-induced linear lesions. The
      ablation will be randomized to a linear encircling around the ipsilateral PVs with the
      endpoint of complete PV isolation proven by two circumferential mapping catheters versus the
      same ablation procedure which will be terminated instantaneously when total PV isolation
      occurs, thereby allowing at least one conduction gap along the isolation line. An invasive
      re-evaluation is scheduled after 3 months for all pts to assess longterm PV conduction
      properties.
    

Intervention name(s): Pulmonary vein ablation
Intervention type(s): Procedure
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Atrial fibrillation; Pulmonary vein ablation; Linear lesions