Paper published in the Journal of Thoracic and Cardiovascular Surgery: congrats Niels Harlaar!

Besides his pre-clinical research on experimental AF models, Niels Harlaar also focuses on the clinical aspects of this rhythm disorder. Under supervision of Thomas van Brakel (cardiothoracic surgeon and principal investigator), Niels has investigated so-called clamping vs non-clamping devices in thoracoscopic box ablation in AF.

Below you can find the abstract of his paper, which has been accepted by the Journal of Thoracic and Cardiovascular Surgery as a result of a succesful collaboration between different hospitals.

Clamping vs Non-Clamping Thoracoscopic Box Ablation in Long-Standing Persistent Atrial Fibrillation

Niels Harlaar1,2, BSc; Niels J. Verberkmoes3, MD; Pepijn H. van der Voort4, MD; Serge A. Trines2, MD, PhD; Stefan E. Verstraeten3, MD; Bart J.A. Mertens, PhD5, Robert J.M. Klautz1, MD, PhD; Jerry Braun1, MD, PhD; Thomas J. van Brakel1, MD, PhD

1 Department of Cardiothoracic Surgery, Leiden University Medical Center, 2 Department of Cardiology, Leiden University Medical Center, 3 Department of Cardiothoracic Surgery, Catharina Hospital Eindhoven, 4 Department of Cardiology, Catharina Hospital Eindhoven, 5 Department of Biomedical Data Sciences, Leiden University Medical Center

Objective: To compare clinical outcomes of clamping devices and linear non-clamping devices for isolation of the posterior left atrium (box) in thoracoscopic ablation of long-standing persistent AF (LSPAF).

Methods: Eighty patients who underwent thoracoscopic pulmonary vein (PV) and box isolation using either a bipolar clamping device (42 patients) or bipolar non-clamping device (38 patients) to create the roof/inferior lesions for box isolation were included from two centers. Follow-up consisted of 24-h Holter at regular intervals. Freedom from AF during 1-year follow-up and catheter repeat interventions were compared between groups.

Results: Acute intraoperative electrical isolation of the box compartment was significantly higher in the clamping group compared to the non-clamping group (100% and 79% respectively, p<0.01). At 1-year follow-up, 91% of the clamping group patients and 79% of the non-clamping group patients were in sinus rhythm. During 1-year follow-up, recurrence rates did not significantly differ between the two groups (p=0.08). Repeat catheter interventions were required in 10% of clamping and 21% of non-clamping patients (p=0.15). Here, conduction gaps in the roof and/or inferior lesions were found in 1 patient (2%) in the clamping group versus 4 patients (11%) in the non-clamping group (p=0.13).

Conclusions: Thoracoscopic PV and box isolation is highly effective in restoring sinus rhythm in LSPAF on short term follow-up. Comparison of clamping and non-clamping devices revealed lower rates of intraoperative exit block of the box in the non-clamping group. This, however, did not translate into a significant difference in AF freedom at short-term (1-year) follow-up.