title: The use of quadripolar left ventricular leads improves the hemodynamic response to cardiac resynchronization therapy.
abstract: BACKGROUND
  The objective of the present study was to evaluate the usefulness of a left ventricle (LV) quadripolar lead in improving the hemodynamic response to cardiac resynchronization therapy (CRT).
  
  
  RESULTS
  We included 27 consecutive patients implanted with a CRT device with an LV quadripolar lead. Hemodynamic parameters were evaluated at 3-month follow-up by using impedance cardiography. We assessed the highest cardiac output and the highest stroke volume (SV) obtained after atrioventricular and interventricular optimization with pacing from each of the four electrodes of the LV lead. Each patient was evaluated according to three different pacing configurations: unipolar-simulated, bipolar, and quadripolar. Biventricular pacing improved hemodynamics in comparison to the nonpaced measurements: cardiac index (CI): 2.69 L/min/m(2) versus 2.17 L/min/m(2) (P = 0.001). The hemodynamic response was highest in the quadripolar in comparison to unipolar-simulated and bipolar configurations, with an increase of 29%, 23%, and 27%, respectively, in relation to the reference CI and with an increase of 22%, 11%, and 18%, respectively, in relation to the reference indexed SV (P < 0.05, for the comparison between unipolar-simulated and quadripolar configurations). Twelve patients (44%) showed the best hemodynamic response by pacing from any of the two distal electrodes and 15 patients (56%) by pacing from the two proximal electrodes. Finally, CRT responder rates were higher in quadripolar versus bipolar and unipolar-simulated configurations: 90%, 85%, and 75%, respectively.
  
  
  CONCLUSIONS
  The quadripolar LV lead was associated with a better hemodynamic response and higher CRT responder rates when compared with unipolar-simulated and bipolar LV leads.
authors.affiliation: Electrophysiology Section, Cardiology Department, Hospital Universitari i Politècnic La Fe, Valencia, Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Osca
authors.forename: Pau
authors.initials: P
authors.lastname: Alonso
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Cano
authors.forename: Juan Miguel
authors.initials: JM
authors.lastname: Sánchez
authors.forename: David
authors.initials: D
authors.lastname: Tejada
authors.forename: Ana
authors.initials: A
authors.lastname: Andrés
authors.forename: María José
authors.initials: MJ
authors.lastname: Sancho Tello
authors.forename: José
authors.initials: J
authors.lastname: Olagüe
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D010791:Phrenic Nerve / Q000502:physiology; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology* / Q000628:therapy*
keywords: cardiac resynchronization; phrenic; quadripolar lead; responder