Tied up in the Lab: An Unexpected Catheter Knot in the Arterial System

Catheter knotting is a rare but potentially serious complication encountered during electrophysiological procedures. We report an unusual case of catheter ablation for premature ventricular complexes (PVCs) arising from anterolateral papillary muscle, where a ThermoCool SmartTouch (ST) catheter (Biosense Webster, Irvine, CA) developed a knot within the arterial system during transaortic mapping. The knot formed after the catheter was inadvertently withdrawn into the ascending aorta and re-advanced, leading to looping and tip entrapment. Standard maneuvers to untie the knot were unsuccessful. As a novel bailout strategy, the external portion of the catheter was cut near the handle and a large-bore 8.5 SL0 sheath (Swartz Braided SL Transseptal Guiding Introducer Sheath; length 63 cm) was advanced over it. The knotted catheter was then maneuvered against the aortic valve, and controlled mechanical contact led to successful loosening of knot and sheath retrieval. This case underscores the importance of early recognition, careful manipulation, and innovative problem-solving in managing rare mechanical complications in the cardiac electrophysiology lab.