title: Use of a quadripolar left ventricular lead to achieve successful implantation in patients with previous failed attempts at cardiac resynchronization therapy.
abstract: OBJECTIVE
  Problems with implanting a left ventricular (LV) lead during cardiac resynchronization therapy (CRT) procedures are not uncommon and may occur for a variety of reasons including phrenic nerve stimulation (PNS) and high capture thresholds. We aimed to perform successful CRT in patients with previous LV lead problems using the multiple pacing configurations available with the St Jude Quartet model 1458Q quadripolar LV lead to overcome PNS or high capture thresholds.
  
  
  RESULTS
  Four patients with previous failed attempts at LV lead implantation underwent a further attempt at CRT using a Quartet lead. In all four cases, successful CRT was achieved using a Quartet lead placed in a branch of the coronary sinus. Problems with PNS or high capture thresholds were seen in all four patients but were successfully overcome. Satisfactory lead parameters were seen at implant, pre-discharge, and at short-term follow-up (8.5±5 weeks).
  
  
  CONCLUSIONS
  The Quartet lead allows 10 different pacing vectors to be used and may overcome common pacing problems because of the multiple pacing configurations available. Problems with either PNS or unsatisfactory pacing parameters experienced during CRT may be resolved simply by changing the pacing configuration using this quadripolar lead system.
authors.affiliation: Cardiothoracic Department, Guys and St Thomas' Hospital NHS Foundation Trust, and King's College London, London, UK. anoop.shetty@kcl.ac.uk
authors.forename: Anoop K
authors.initials: AK
authors.lastname: Shetty
authors.forename: Simon G
authors.initials: SG
authors.lastname: Duckett
authors.forename: Julian
authors.initials: J
authors.lastname: Bostock
authors.forename: Eric
authors.initials: E
authors.lastname: Rosenthal
authors.forename: C Aldo
authors.initials: CA
authors.lastname: Rinaldi
mesh_terms: D000328:Adult; D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D009202:Cardiomyopathies / Q000503:physiopathology* / Q000628:therapy*; D054326:Coronary Sinus / Q000503:physiopathology; D004567:Electrodes, Implanted; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000503:physiopathology; D017211:Treatment Failure; D016896:Treatment Outcome