title: Impact of right-ventricular apical pacing on the optimal left-ventricular lead positions measured by phase analysis of SPECT myocardial perfusion imaging.
abstract: OBJECTIVE
  The use of SPECT phase analysis to optimize left-ventricular (LV) lead positions for cardiac resynchronization therapy (CRT) was performed at baseline, but CRT works as simultaneous right ventricular (RV) and LV pacing. The aim of this study was to assess the impact of RV apical (RVA) pacing on optimal LV lead positions measured by SPECT phase analysis.
  
  
  METHODS
  This study prospectively enrolled 46 patients. Two SPECT myocardial perfusion scans were acquired under sinus rhythm with complete left bundle branch block and RVA pacing, respectively, following a single injection of (99m)Tc-sestamibi. LV dyssynchrony parameters and optimal LV lead positions were measured by the phase analysis technique and then compared between the two scans.
  
  
  RESULTS
  The LV dyssynchrony parameters were significantly larger with RVA pacing than with sinus rhythm (p ~0.01). In 39 of the 46 patients, the optimal LV lead positions were the same between RVA pacing and sinus rhythm (kappa = 0.861). In 6 of the remaining 7 patients, the optimal LV lead positions were along the same radial direction, but RVA pacing shifted the optimal LV lead positions toward the base.
  
  
  CONCLUSIONS
  The optimal LV lead positions measured by SPECT phase analysis were consistent, no matter whether the SPECT images were acquired under sinus rhythm or RVA pacing. In some patients, RVA pacing shifted the optimal LV lead positions toward the base. This study supports the use of baseline SPECT myocardial perfusion imaging to optimize LV lead positions to increase CRT efficacy.
authors.affiliation: Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan.
authors.forename: Guang-Uei
authors.initials: GU
authors.lastname: Hung
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Huang
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Lin
authors.forename: Shih-Chung
authors.initials: SC
authors.lastname: Tsai
authors.forename: Kuo-Yang
authors.initials: KY
authors.lastname: Wang
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lloyd
authors.forename: Ji
authors.initials: J
authors.lastname: Chen
mesh_terms: D000368:Aged; D001146:Arrhythmia, Sinus / Q000000981:diagnostic imaging / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D017256:Technetium Tc 99m Sestamibi / Q000627:therapeutic use; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi