CASE COMMUNICATIONS 123 20 2018 electrode knotting, temporary pacemaker complication, snaring, permanent pacemaker, pacemaker lead entrapment IMAJ 2018; 20: 123–124 and developed a complete atrioventricular block during the procedure. A temporary wire was introduced as back-up via the right subclavian vein and was lef in place. During the following 24 hours the patient remained pacemaker-dependant and was transferred to the electrophysiology laboratory for per- manent pacemaker implantation. A dual chamber pacemaker was implanted through the lef subclavian vein. At the end stages of the procedure (when the electrodes were already positioned in the right ventricle apex and right atrial append- age) the temporary wire was carefully pulled out of the right ventricle (RV). However, a loop that was created while placing the temporary pacemaker caught the perma- nent ventricular lead that was inadvertently placed through the temporary wire loop [Figure 1A]. As we tried to pull out the temporary electrode, it formed a tight knot on the permanent ventricular lead, which A n unusual obstacle happened during implantation of a ventricular perma- nent pacemaker (PPM) lead in a patient with a temporary pacemaker (TPM). Te PPM electrode was entrapped in a knot cre- ated by a loop of the TPM electrode. Te external part of the TPM electrode was cut and the lead with a knot was extracted by snaring it through the lef femoral vein. PATIENT DESCRIPTION A 71 year old patient underwent trans- catheter aortic valve implantation (TAVI) was partially extracted from the apex while pulling the temporary lead. We lost capture for a few seconds. Te permanent lead was pushed forward and placed immediately back to the RV apex but then the previously open loop of the temporary wire created a knot that entrapped the permanent wire making it impossible to pull the temporary wire out without risking pulling the perma- nent lead as well [Figure 1B]. A second ventricular lead was placed in the RV apex via the lef subclavian vein. Afer multiple attempts, we succeeded in removing the trapped permanent ven- tricular lead from the loop of the temporal pacemaker electrode. We were lef with the temporary wire through the right subclavian vein with a sizable knot mak- ing it hazardous to pull it through the vein, which could tear, making it difcult to control bleeding at the site. Te external part of the temporary pacemaker electrode KEY WORDS: Entrapment of Permanent Pacemaker Ventricular Lead in a Loop Formed by a Temporary Pacemaker Electrode. How to Untie a Tight Knot? Roman Nevzorov MD 1 , Sergey Litvin MD 2 , Michael Knizhnik MD 2 , Boris Strasberg MD 1 and Moti Haim MD 1 1 Departments of Cardiology and 2 Diagnostic Radiology, Rabin Medical Center (Beilinson Campus), Petah Tikva, associated with Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Figure 1. [A] A loop that was created while placing the temporary pacemaker [B] A knot created by the previously open loop of the temporary wire B A