Correlation Of The Electrical Parameters Of The Thoracoscopic Radiofrequency Ablation Of Atrial Fibrillation With Two-year Rhythm Maintenance
Anna Witkowska1, Grzegorz Suwalski2, Maciej Bartczak1, Dominik Drobinski1, Radoslaw Smoczynski1, Mariusz Kowalewski1, Jakub Staromlynski1, Piotr Suwalski, PhD1.
1Central Clinical Hospital of the Ministry of Interior in Warsaw, Warsaw, Poland, 2Military Institute of Medicin in Warsaw, Warsaw, Poland.
Background:Bipolar radiofrequency surgical ablation is one of the most effective methods of the treatment of atrial fibrillation (AF). During ablation, current bipolar radiofrequency (RF) devices measure electrical parameters to optimize it and indicate the moment when transmural ablation has been obtained. Those parameters are directly associated with the electrical characteristics of the tissue, thus they may be a marker for long-term outcomes. Aim:We sought to determine whether the electrical parameters of bipolar radiofrequency ablation to achieve an acute conduction block during pulmonary vein isolation (PVI) measured by the device have an impact on the long-term rhythm outcome.Materials and Methods: In 76 consecutive patients (55 males, mean age of 59 (+/-9) years) undergoing totally thoracoscopic ablation of persistent AF, electrical parameters of radiofrequency ablation were collected. The measured data included a number of energy applications and reposition of clamps, the total energy of RF in Watts and a total time of ablation required for intraoperative conduction block. The mean duration of arrhythmia was 92(+/-8) months. All patients had performed pulmonary vein isolation, connecting lines on the posterior wall of the left atrium and left atrial appendage exclusion. The rhythm was assessed using 24-hour Holter monitoring performed after 6,12 and 24 months.Results:The perioperative period was uneventful. Sinus rhythm was present in 61(80%) and 57(75%) of patients after 12 and 24 months, respectively. In all patients acute conduction block was achieved. Patients with atrial fibrillation recurrence required more applications and longer time of energy delivery to achieve isolation of the right pulmonary veins (38(+/-32) vs 24(+/-15);p=0,011 and 230(+/-197) vs 149(+/-85);p=0,015 respectively). In recurrence cohort more applications (38(+/-32) vs 18(+/-11);p=0,005) and longer time of ablation (230(+/-197) vs (111(+/-72);p=0,001) were observed to achieve PVI on the right than on the left side. Conclusions: More energy and the number of applications, especially on the right pulmonary veins, needed to achieve an acute conduction block during bipolar radiofrequency ablation is a marker of arrhythmia recurrence in the longer follow-up. It may indicate higher fibrosis of the left atrium.
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