title: Active fixation of a thin transvenous left-ventricular lead by a side helix facilitates targeted and stable placement in cardiac resynchronization therapy.
abstract: OBJECTIVE
  Suboptimal placement, phrenic nerve stimulation, and dislodgements of left-ventricular (LV) leads are main challenges in cardiac resynchronization therapy. We investigated the handling, performance, safety, and stability for a novel 4Fr LV lead with a small side helix located proximal to the ring electrode for active fixation of the LV lead.
  
  
  RESULTS
  The novel LV lead was successfully implanted in 103 of 106 patients. Patients with dislodged LV leads and with demanding coronary vein anatomies were included. The lead body was rotated clockwise to engage the active fixation side helix in the vein wall. The stimulating electrode was located in basal LV segment and middle LV segment in 54 and 46% of the patients, respectively. The lead was targeted to a vein concordant to the LV segment with latest mechanical activation. Concordant LV lead placement was achieved in 73% of the patients and in adjacent segment in 24%. The average pacing capture threshold (PCT) at implantation was 1.04 ± 0.6 V (n = 103) and at an average follow-up at 7 months, the PCT remained low and no dislodgements have been observed. During follow-up, four leads have been explanted without complications.
  
  
  CONCLUSIONS
  Active fixation of this 4Fr LV lead by using a side helix, offers flexibility to place the lead precisely in targeted vein segments over a wide range of vein anatomies. The average LV pacing threshold was low at implantation and follow-ups. The lead seems to be extractable and no late dislodgements have been observed.
authors.affiliation: Department of Heart Disease, Haukeland University Hospital, Bergen, Norway hkei@helse-bergen.no.
authors.forename: Håvard
authors.initials: H
authors.lastname: Keilegavlen
authors.affiliation: Department of Heart Disease, Haukeland University Hospital, Bergen, Norway.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hovstad
authors.affiliation: Department of Heart Disease, Haukeland University Hospital, Bergen, Norway Department of Clinical Science, University of Bergen, Bergen, Norway.
authors.forename: Svein
authors.initials: S
authors.lastname: Færestrand
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D004567:Electrodes, Implanted; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway; D010690:Phlebography; D010791:Phrenic Nerve / Q000503:physiopathology; D016896:Treatment Outcome
keywords: Active fixation; Cardiac resynchronization therapy; Lead dislodgement; Left ventricular lead placement