title: Potential benefit of Bachmann's bundle pacing on left ventricular performance in patients with cardiac resynchronized therapy.
abstract: BACKGROUND
  Right atrial (RA) appendage (RAA) pacing is reported to impair hemodynamic benefits of cardiac resynchronization therapy (CRT) through a considerable delay of left atrial (LA) contraction, which compromises appropriate balance of atrioventricular (AV) and left ventricular (LV) synchrony. Potential usefulness of Bachmann's bundle (BB) pacing to solve the problem remains to be confirmed.
  
  
  RESULTS
  Atrial synchrony and LV performance was investigated by echocardiography in 25 patients undergoing pacemaker implantation with preserved AV conduction and LV function (Group I), and 15 patients receiving CRT (Group II). In Group I, RAA pacing (AAI mode, n=10) increased P-wave duration (PWD) and RA-to-LA contraction delay (IAMD) compared with sinus rhythm (132±14 and 35±12 ms vs. 108±16 and 13±13 ms, P<0.001). The delayed LA contraction was associated with early interruption of LV filling, leading to an impairment of LV performance (Tei index: 0.43±0.12 vs. 0.34±0.09, P<0.01). BB pacing (AAI, n=15) did not cause such undesirable effects. In Group II, RA (BB)-paced biventricular pacing (DDD) reduced PWD and IAMD compared with RA-sensed biventricular pacing (VDD) (102±14 and -3±13 ms vs. 117±10 and 21±18 ms, P<0.001). This restoration of atrial synchrony was associated with significant improvement of LV performance (Tei index: 0.56±0.18 vs. 0.62±0.16, P<0.05).
  
  
  CONCLUSIONS
  BB pacing preserves atrial synchrony, and might be more favorable than RAA pacing for maximizing hemodynamic efficacy of CRT.
authors.affiliation: Division of Arrhythmia and Electrophysiology, Shizuoka Saiseikai General Hospital, Shizuoka, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Suzuki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Osaka
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kuroda
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hasebe
authors.forename: Eriko
authors.initials: E
authors.lastname: Yokoyama
authors.forename: Kaichiro
authors.initials: K
authors.lastname: Kamiya
authors.forename: Itsuo
authors.initials: I
authors.lastname: Kodama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D058406:Cardiac Resynchronization Therapy; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D020127:Recovery of Function; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left