title: Synchronous ventricular pacing without crossing the tricuspid valve or entering the coronary sinus--preliminary results.
abstract: BACKGROUND
  Right ventricular apical (RVA) pacing promotes tricuspid regurgitation (TR), electromechanical dyssynchrony, and ventricular dysfunction. We tested a novel intramyocardial bipolar lead to assess whether stimulation of the atrioventricular septum (AVS) produces synchronous ventricular activation without crossing the tricuspid valve (TV).
  
  
  METHODS
  A lead with an active external helix and central pin was placed on the AVS and the RVA in three dogs. High-density electroanatomic (EA) mapping was performed of both ventricles endocardially and epicardially. Intracardiac echocardiography was used to access ventricular synchrony.
  
  
  RESULTS
  The lead was successfully deployed into the AVS in all cases with consistent capture of the ventricular myocardium without atrial capture or sensing. The QRS duration was less with AVS compared with RVA pacing (89 +/- 4 ms vs. 100 +/- 11 ms [P < 0.0001, GEE P = 0.03]). There was decreased delay between color Doppler M-mode visualized peak contraction of the septum and the mid left ventricular free wall with AVS compared with RVA pacing (89 +/- 91 ms vs. 250 +/- 11 ms [P < 0.0001, GEE P = 0.006]). Activation time between the mid septum and mid free wall was shorter with AVS versus RVA pacing (20.4 +/- 7.7 vs. 30.8 +/- 11.6 [P = 0.01, GEE P = 0.07]). The interval between QRS onset to earliest free wall activation was shorter with AVS vs. RVA pacing (19.2 +/- 6.4 ms vs. 31.1 +/- 11.7 ms [P = 0.005, GEE P = 0.02]).
  
  
  CONCLUSIONS
  The AVS was successfully paced in three dogs resulting in synchronous ventricular activation without crossing the TV.
authors: Division of Cardiovascular Diseases and Internal Medicine Mayo Clinic, Rochester, Minnesota 55905, USA.
authors: Benhur D
authors: BD
authors: Henz
authors: Paul A
authors: PA
authors: Friedman
authors: Charles J
authors: CJ
authors: Bruce
authors: Yasuo
authors: Y
authors: Okumura
authors: Susan B
authors: SB
authors: Johnson
authors: Andrew
authors: A
authors: Danielsen
authors: Douglas L
authors: DL
authors: Packer
authors: Samuel J
authors: SJ
authors: Asirvatham
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D054326:Coronary Sinus / Q000503:physiopathology*; D004285:Dogs; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D010865:Pilot Projects; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000503:physiopathology*