title: Usefulness of electroanatomical mapping during transseptal endocardial left ventricular lead implantation.
abstract: OBJECTIVE
  Failure rate to implant left ventricular (LV) lead transvenously is 4-8% in cardiac resynchronization therapy (CRT) patients. Epicardial lead placement is an alternative method and if not applicable case reports and small series showed the feasibility of endocardial LV lead implantation. Electroanatomical mapping might be a useful tool to guide this procedure.
  
  
  RESULTS
  Four patients had undergone endocardial LV lead implantation after unsuccessful transvenous implantation or epicardial LV lead dysfunction using the transseptal approach. Electroanatomical mapping was used to mark the location of the transseptal puncture. This location point guided the mapping catheter from the subclavian access and facilitated positioning of the LV lead at the adjacent latest activation area of the left ventricle detected by activation mapping. Endocardial active fixation LV leads were successfully implanted in all patients with stable electrical parameters immediately after implantation and over a mean follow-up of 18.3 months (lead impedance 520 ± 177 vs. 439 ± 119 Ω and pacing threshold 0.8 ± 0.2 V, 0.5 ms vs. 0.6 ± 0.1 V, 0.5 ms, respectively). Patients were maintained on anticoagulation therapy with a target international normalized ratio of 3.5-4.5 and did not show any thromboembolic, haemorrhagic events, or infection. Echocardiography showed significant improvement of LV systolic function with marked improvement of the functional status.
  
  
  CONCLUSIONS
  Electroanatomical mapping is a useful technical tool to guide endocardial LV lead implantation. It helps to identify the location of the transseptal puncture and the use of activation mapping might facilitate location of the optimal lead positions during CRT.
authors.affiliation: Semmelweis University, Heart Center, Városmajor utca 68, Budapest, Hungary.
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
authors.forename: Béla
authors.initials: B
authors.lastname: Merkely
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Szilágyi
authors.forename: Endre
authors.initials: E
authors.lastname: Zima
authors.forename: Attila
authors.initials: A
authors.lastname: Róka
authors.forename: Akos
authors.initials: A
authors.lastname: Király
authors.forename: István
authors.initials: I
authors.lastname: Osztheimer
authors.forename: Levente
authors.initials: L
authors.lastname: Molnár
authors.forename: Gábor
authors.initials: G
authors.lastname: Széplaki
authors.forename: László
authors.initials: L
authors.lastname: Gellér
mesh_terms: D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D004567:Electrodes, Implanted; D004699:Endocardium / Q000601:surgery; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000517:prevention & control*; D006346:Heart Septum / Q000601:surgery; D006352:Heart Ventricles / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000379:methods*