Abstract
An 82-year-old man who had undergone Watchman FLX (Boston Scientific) device implantation presented with dyspnea. Multimodality evaluation demonstrated a small fistula from the proximal circumflex artery to the left atrial appendage. Anatomically, the left circumflex artery is close to the atrial appendage; therefore, it is plausible that fistula formation could be a late complication of implantation of the device.