The procedure consisted of a video-thoracoscopic, bilateral, close-chest approach to both deliver a continuous lesion encircling the origin of all pulmonary veins (box lesion set), and exclude the left atrial appendage. Under general anesthesia, intubation with double-lumen endotracheal tube for selective lung ventilation, and transesophageal echocardiography (TEE) to confirm the presence of thrombi in the left atrial appendage (LAA) are carried out. Defibrillator pads are placed before surgery. The patient is positioned supine. In order to widely expose the anterior axillary line, both arms are slightly flexed and a small inflatable pillow is placed beneath the scapula on each side. Port-access points are then marked bilaterally: for the camera and CO2 insufflation port in the 3^rd intercostal space on the anterior axillary line, and for the instrumentation ports in the 2^nd and the 5^th intercostal spaces, slightly anteriorly to delineate a triangle with the base parallel to the sternum and the apex at the level of the camera port. Conversely, in the left thorax the instrumentation ports are marked approximately in the mid-axillary line, and the 6^th intercostal space is chosen instead of the 5^th in longitypes.

At the first step, the right pillow is inflated to angle the patient on the left decubitus of approximately 30°. The right thorax is then entered during single left-lung ventilation. Three ports are placed after a 12–mm incision at the level of marked points. In order to pressurize the pleural space and the intra-pericardial space, CO2 insufflation is started (3 to 5 liters/minute) and a rigid video-thoracoscopic (VTS) camera is inserted.