Thoracoscopic infrared ablation to create a box lesion as a treatment for atrial fibrillation

Abstract

Background: Creating a box lesion in the posterior wall of the left atrium from the epicardial side of the beating heart remains a challenge. Although a transmural lesion can be created by applying radiofrequency (RF) energy at clampable sites, it is still difficult to create a transmural lesion at unclampable sites because the inner blood flow in the unclampable free wall weakens the thermal effect on the outside. Our aim was to apply the newly developed infrared coagulator to create linear transmural lesions on the beating heart thoracoscopically to treat atrial fibrillation (AF).

Case presentation: A 71-year-old male was referred to our hospital with a diagnosis of hypertrophic cardiomyopathy and permanent atrial fibrillation. The patient was first diagnosed with atrial fibrillation 20 years before. Direct current cardioversion had been performed every few years a total of four times, but sinus rhythm restoration had always been temporary. On February 27, 2020, thoracoscopic PV isolation together with infrared roof- and bottom-line ablation to create a box lesion and left atrial appendage amputation (LAAA) were performed. The coagulator could be applied to clinical thoracoscopic surgery to successfully create a box lesion without any complication. The patient restored a regular sinus rhythm, it has been maintained for eleven months, and there have been no adverse events.

Conclusions: The infrared coagulator might have enough potential to create transmural lesions on the beating heart in thoracoscopic AF surgery.

Keywords: Ablation; Atrial fibrillation; Box lesion; Epicardial ablation; Epicardial maze procedure; Ex-maze procedure; Infrared; Infrared coagulator; Left atrial appendage amputation; Thoracoscopic surgery.

Fig. 1

Infrared coagulator “Kyo-co”. a Body of the coagulator. It is connected to a light-guide, foot switch, and vacuum system to cool the light-guide. b Light-guide reinforced with heat-resistant plastic equipped with a light conducting 8-mm diameter curved-tip quartz rod. c Exit plane

Fig. 2

Operating room. Four endoscopic ports were created in the left lateral thorax: one for a 5-mm, 45-degree endoscope, another for an endoscopic cutter, and the other two for endo-forceps

Fig. 3

Endoscopic view of the left atrium. a Ablation of the left side of the roof of the left atrium. Several overlapping lesions were created to form a linear lesion. An ablated discolored lesion is clearly visible. b Ablation of the left side of the bottom of the left atrium. A wide, clear visual field can be obtained with a 45-degree endoscope