title: Antiarrhythmic effect of cardiac resynchronization therapy with triple-site biventricular stimulation.
abstract: OBJECTIVE
  The antiarrhythmic effect of triple-site biventricular stimulation (Tri-V) is poorly understood. This study aims to evaluate the effect of cardiac resynchronization therapy (CRT) on ventricular arrhythmia (VA) with Tri-V using a single right ventricular (RV) and double left ventricular (LV) lead.
  
  
  RESULTS
  Over a period of 3.5 years, 58 consecutive patients with New York Heart Association class II-IV heart failure, an LV ejection fraction of ≤ 0.35, and a QRS interval of ≥ 120 ms were enrolled. Acute haemodynamic responses to dual-site biventricular stimulation (Bi-V) and Tri-V were evaluated by assigning patients to a Bi-V or Tri-V group. Electrocardiogram parameters [QT interval, JT interval, and transmural dispersion of repolarization (TDR)] were measured over time after CRT. Spontaneous VA detected by telemetry was reviewed and confirmed. During a mean follow-up of 481 days after implantation, VA occurred in 2 of 22 patients in the Tri-V group and 14 of 36 patients in Bi-V group. Triple-site biventricular stimulation was thus associated with a decreased VA risk (P = 0.044). Multivariate Cox analysis showed that Tri-V pacing prevented arrhythmic events as compared with Bi-V pacing (hazard ratio, 0.13; 95% confidence interval, 0.029-0.610; P = 0.009). Ventricular repolarization indices at 6 months were significantly shortened in Tri-V compared with Bi-V (QTc, -23.6 vs. -14.1%, P = 0.008; JTc, -21.4 vs. -7.7%, P = 0.005; TDRc, -39.9 vs. -17.0%, P < 0.001).
  
  
  CONCLUSIONS
  Compared with Bi-V, Tri-V reduced VA during long-term follow-up. Improvements in repolarization parameters may result in antiarrhythmic effects.
authors.affiliation: Division of Cardiology, Shizuoka Medical Center, 762-1 Nagasawa, Shimizu, Sunto, Shizuoka 4110906, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Ogano
authors.forename: Yu-ki
authors.initials: YK
authors.lastname: Iwasaki
authors.forename: Jun
authors.initials: J
authors.lastname: Tanabe
authors.forename: Hisato
authors.initials: H
authors.lastname: Takagi
authors.forename: Takuya
authors.initials: T
authors.lastname: Umemoto
authors.forename: Meiso
authors.initials: M
authors.lastname: Hayashi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyauchi
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Mizuno
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D016009:Chi-Square Distribution; D004562:Electrocardiography; D004867:Equipment Design; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D013318:Stroke Volume; D013686:Telemetry; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
keywords: Antiarrhythmia; Cardiac resynchronization therapy; Multi-site pacing; Ventricular arrhythmia; Ventricular repolarization.