title: Improvement in hemodynamic response using a quadripolar LV lead.
abstract: BACKGROUND
  The Quartet quadripolar lead (St. Jude Medical Inc., St. Paul, MN, USA) offers 10 different left ventricle pacing configurations that may further influence hemodynamic parameters compared to traditional bipolar pacing configurations. The purpose of this study was to evaluate whether pacing from additional quadripolar lead vectors could enhance cardiac output (CO).
  
  
  METHODS
  For each patient, CO was measured in "no-pacing" and in all the 10 configurations available, within 7 days of implantation of the device. Tip-ring, tip-right ventricular coil (RVC), and ring-RVC vectors were considered as traditional vectors. The seven additional configurations available in the quadripolar lead were considered as nontraditional vectors. CO was measured by ECHO. The best configuration was defined as the one presenting the highest CO measurement within configurations, which have a capture threshold <3 V and a safety margin between the capture and the phrenic nerve stimulation thresholds.
  
  
  RESULTS
  Fifty-one standard cardiac resynchronization therapy patients were enrolled. The mean of each patient's best CO obtained with traditional vectors was higher than the baseline nonpaced CO (4.16 L/min vs 3.64 L/min). The mean of each patient's best CO, including all 10 available configurations, was also higher than the baseline nonpaced CO (4.33 L/min vs 3.64 L/min). In addition, the mean of each patient's best CO obtained with the best configuration available through a quadripolar lead was better than the mean of each patient's best CO obtained with a traditional configuration. In 53% of patients, the best CO was obtained with a nontraditional vector unique to the quadripolar lead.
  
  
  CONCLUSIONS
  A quadripolar lead offers multiple additional pacing options to increase CO acutely compared to conventional bipolar leads.
authors.affiliation: Hospital Universitario Virgen de Victoria, Málaga, Spain. fonendo@hotmail.com
authors.forename: Fernando
authors.initials: F
authors.lastname: Cabrera Bueno
authors.forename: Javier
authors.initials: J
authors.lastname: Alzueta Rodríguez
authors.forename: José
authors.initials: J
authors.lastname: Olagüe de Ros
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernández-Lozano
authors.forename: Juan José
authors.initials: JJ
authors.lastname: García Guerrero
authors.forename: Joaquín Fernández
authors.initials: JF
authors.lastname: de la Concha
authors.forename: Antonio
authors.initials: A
authors.lastname: Hernández Madrid
authors.forename: Jose María
authors.initials: JM
authors.lastname: Tolosana Viu
authors.forename: Joaquín
authors.initials: J
authors.lastname: Osca Asensi
authors.forename: Alberto
authors.initials: A
authors.lastname: Barrera Cordero
authors.forename: Elena
authors.initials: E
authors.lastname: Llorente Hernangómez
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D058409:Cardiac Resynchronization Therapy Devices; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control*
keywords: cardiac output; cardiac resynchronization; quadripolar lead