Clinical approach to the knotting diagnostic quadripolar catheter during zero‐fluoro electrophysiological study

: We report a case of electrophysiology catheter knotting when inserted without fluoroscopic guidance followed by technique to unravel the knot via ipsilateral femoral vein. We advocate caution when manipulating catheters using minimal/zero fluoroscopic technique and having a low threshold to screen under fluoroscopy when encountering difficulties during catheter insertion.