title: Inter- and intravein differences in cardiac output with cardiac resynchronization pacing using a multipolar LV pacing lead.
abstract: BACKGROUND
  Quadripolar left ventricular pacing leads permit a variety of pacing configurations from different sites within a coronary vein. There may be advantages to selecting a specific pacing vector. This study examines whether the range of cardiac outputs obtained at cardiac resynchronization therapy (CRT) implantation is greater between different poles within a vein, or greater between two different veins.
  
  
  RESULTS
  The cardiac index (CI, L/min/m(2) ) was measured during CRT implantation using a noninvasive cardiac output monitor (NICOM™, Cheetah Medical Inc., Newton Center, MA, USA) and a quadripolar left ventricle (LV) lead, in 22 patients with sinus rhythm. CI was recorded during right atrial-biventricular pacing at 70/min with fixed atrioventricular and ventriculo-ventricular delay, from each LV electrode in one vein, and then from an alternate vein. Phrenic nerve stimulation (PNS) occurred in nine of 15 posterior and three of 21 anterior veins (P = 0.005). At least one electrode in each vein had no PNS. The mean (standard deviation [SD]) difference between best and worst CI within any one vein was 13.1% (±9%). The mean (SD) difference between the best CI in one vein compared to the other was 9.8% (±8%; P = 0.043). In 16 of 22 patients, the range of CI was greater between poles within one vein, rather than between two veins (best of one vein compared to best from the other). In four of 22 patients, the range was greater between veins (P = 0.0003).
  
  
  CONCLUSIONS
  A greater range of CI is found within a single vein than between two different veins. This finding has implications both for the approach to implant technique and postimplant programming and optimization.
authors.affiliation: From the Cardiology Department, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Headington, Oxfordshire, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Jones
authors.forename: Raj
authors.initials: R
authors.lastname: Khiani
authors.forename: Paul
authors.initials: P
authors.lastname: Foley
authors.forename: David
authors.initials: D
authors.lastname: Webster
authors.forename: Norman
authors.initials: N
authors.lastname: Qureshi
authors.forename: Kelvin C K
authors.initials: KC
authors.lastname: Wong
authors.forename: Kim
authors.initials: K
authors.lastname: Rajappan
authors.forename: Yaver
authors.initials: Y
authors.lastname: Bashir
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Betts
mesh_terms: D000368:Aged; D002302:Cardiac Output; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D003331:Coronary Vessels / Q000503:physiopathology*; D004567:Electrodes, Implanted; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D016896:Treatment Outcome
keywords: CRT; NICOM; cardiac output; multipolar; optimization; quartet