Introduction:
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia which  occurs in 1-2% of the general population. In the case of persistent atrial fibrillation arrhythmia, despite improved ablation techniques and permanently isolated pulmonary veins (PV), a comparably low success rate with regard to freedom from atrial fibrillation is evident. Therefore, ablation of extrapulmonary foci in persistent atrial fibrillation including the isolation of the left arterial appendage (LAA) is an accepted therapy. However, cording to current expert opinion, an interventional closure of the LAA using an occluder is recommended. Implantation of a LAA occluder can prevent ischemic stroke and avoid anticoagulation therapy. Currently, different LAA occluders are available. Complication rates are generally low. In this article, a compression in the left circumflex artery after implantation of an LAA occluder and it treatment is reported.

Case report:
A 52 years old men was referred to our hospital for catheter ablation (PVI) of persistent AF. After initial pulmonary vein isolation by antral pressure-guided radiofrequency encircling of the septal and lateral pulmonary veins with 3D Mapping System (Carto 3TM, Biosense Webster, USA) 09/2019,  recurrence of AF was seen 7 month later. Therefore, alcohol ablation of the marshall vein was performed as a standalone procedure. Due to renewed recurrence of AF  in 03/2020 extensive left atrial re-ablation, including  substrate-based isolation of the posterior and anterior atrial wall, the mitral valve isthmus and the LAA was performed. Postoperative ECG´s were unremarkable, patient was discharged without any symptoms. According to current expert opinion a LAA closure device  (WatchmanTM FLX 27 mm, Boston Scientific, USA) was implanted 20 days after re-ablation to avoid future thromboembolism.

The patient was readmitted 46 day later due to typical angina exacerbated by exertion. Troponin T was within a normal range, a  ECG at rest was unchanged to the previous ECG. Transesophageal echocardiography (TEE) was performed to exclude LAA thrombus. Accordingly, a diagnostic coronary angiography was done, which showed a critical stenosis (Figure 1) of the prox. LCX. There were no atherosclerotic diseases noted in the remaining coronary system. Therefore, we assumed a compression of the LCX on the level of the device. Stenosis was treated by percutaneous coronary intervention with a drug-eluting stent (Promus PremierTM 2,75x32 mm, Boston Scientific, USA) (Figure 2). Control angiography 5 months later showed an unremarkable LCX with a fully expended stent (Figure 3). 

Conclusion:
To our knowledge, this is the first report of a delayed complication after implanting an LAA occluder in literature. In conclusion, interventionalists should consider obstruction of the LCX after implantation of LAA occluders, due to close proximity of the circumflex artery to the LAA. Second-generation, drug-eluting stents with thinner strut thickness, exhibit sufficient radial force and minimum radial recoil when deployed should be preferred in such lesions.