RF Power, LSI and Oesophageal Temperature Alerts During AF Ablation (PiLOT-AF Study)
Condition: Atrial Fibrillation
MeSH terms: Atrial Fibrillation
Study type: Interventional

Summary: 
      Atrial fibrillation (AF) is a very common abnormal heart rhythm, triggered by rapid
      electrical activity originating from the pulmonary veins (PVs) that drain blood from the
      lungs back to the left atrium (LA). Ablation of the junction between the PVs and the LA,
      electrically isolating the veins from the heart, is the key to prevent AF.

      When using radiofrequency energy (RF), transmural lesions are required to achieve permanent
      pulmonary vein isolation (PVI). New technologies are currently available to predict the
      ablation lesion depth and to guide the duration of each application. However, deeper lesions
      mean a higher risk of overheating and damage of adjacent structures such as the esophagus
      that lies against the back wall of the LA. In order to minimize this risk, the investigators
      continuously monitor the temperature inside the esophagus during the procedure through a
      probe placed in the esophagus and they promptly terminate energy delivery in case of any
      esophageal temperature rises more than 39°C.

      To date, it is not known if a low power for a longer time is better than a high power for a
      shorter time when ablating on the LA posterior wall in order to create permanent scars
      without heating the esophagus.

      Therefore, the investigators plan to compare the incidence of esophageal temperature alerts
      and the success of the procedure with four different energy settings during ablation on the
      LA posterior wall.
    

Detailed description: 
      The PiLOT-AF study is a prospective single-centre randomized observational study aiming at
      comparing different radiofrequency energy (RF) settings during atrial fibrillation (AF)
      ablation on the left atrial (LA) posterior wall, in terms of esophageal heating, acute and
      long-term procedure success and procedural complications.

      Patients scheduled for their first RF ablation, because of a history of symptomatic and
      drug-refractory paroxysmal or persistent AF, will be considered for inclusion in the study.

      Potential subjects will initially be approached 4-6 weeks before their ablation procedure, in
      order to give them enough time to consider the information, to ask questions to the
      investigators, their family doctor or other independent parties to decide whether they wish
      to participate in the study or not.

      For those interested in participation, a baseline assessment will be arranged to coincide
      with their standard pre-admission visit, for informed consent, screening and eligibility
      assessment and randomization.

      All AF ablation procedures will be performed in a standard fashion, under general anaesthesia
      and with continuous esophageal temperature monitoring using a sinusoidal multi-sensor
      esophageal temperature probe (CIRCAtemp). After LA geometry reconstruction using
      3-dimensional electroanatomical mapping EnSite Velocity and a multipolar circular mapping
      catheter St Jude Medical Optima, the ablation catheter Endosense Tacticath through a
      deflectable sheath St Medical Agilis will be used for Pulmonary Vein Isolation (PVI).
      Standardized RF settings will be used during ablation on the LA anterior wall as current
      practice in our centre. Different RF settings will be used on the LA posterior wall,
      according to randomization group. Moreover target values will be chosen for Lesion Size Index
      (LSI), a parameter useful to predict the lesion depth, during ablation on LA posterior wall.
      The duration of RF delivery on the LA posterior wall will be dictated by achievement of the
      target LSI or esophageal temperature rise > 39◦C during ablation. PVI will be achieved and
      confirmed after 30 minutes waiting time. In case of acute PV reconnection, ablation at sites
      of breakthrough signals will be performed in order to achieve durable PVI. The occurrence of
      acute PV reconnection (PVR) with sites of breakthrough signals on the LA posterior wall will
      be recorded for each procedure. The total procedure and RF ablation times will be also
      collected.

      After the ablation, before discharge the symptoms status and heart rhythm will be assessed
      and the patient will be instructed to commence a symptoms diary. Telephone follow-ups will be
      then performed at 3 and 6 months to assess current symptom status. Standard care follow-up
      Arrhythmia Clinic visits will be also performed 3-4 months after the ablation procedure. Ad
      hoc visits and/or additional investigations as prolonged electrocardiogram (ECG) monitoring
      will also take place, dictated by arrhythmia symptoms and assessment for potential adverse
      events related to the procedure, in accordance with standard practice.

      The end of the study for each patient will be the date of the 6 months telephone follow-up.
    

Intervention name(s): Combination 1 of radiofrequency (RF) power and Lesion Size Index (LSI) on left atrial (LA) posterior wall; Combination 2 of radiofrequency (RF) power and Lesion Size Index (LSI) on left atrial (LA) posterior wall; Combination 3 of radiofrequency (RF) power and Lesion Size Index (LSI) on left atrial (LA) posterior wall; Combination 4 of radiofrequency (RF) power and Lesion Size Index (LSI) on left atrial (LA) posterior wall
Intervention type(s): Procedure; Procedure; Procedure; Procedure
Intervention description(s): 20 W RF power and target LSI = 4 on LA posterior wall; 40 W RF power and target LSI = 4 on LA posterior wall; 20 W RF power and target LSI = 5 on LA posterior wall; 40 W RF power and target LSI = 5 on LA posterior wall
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: radiofrequency power; lesion size index; esophageal temperature alerts