title: The role of pacing-induced dyssynchrony in left ventricular remodeling associated with long-term right ventricular pacing for atrioventricular block.
abstract: OBJECTIVE
  Patients with atrioventricular (AV) block can develop left ventricular (LV) dysfunction with long-term right ventricular pacing (RVP). We investigated the role of RVP-induced LV dyssynchrony in this adverse remodeling.
  
  
  RESULTS
  Nineteen patients with normal LV function undergoing pacemaker implantation for AV block were included. Right ventricular pacing leads were positioned at the apex. Two-dimensional and tissue Doppler echocardiography was performed before and immediately after implantation and at the end of follow-up. The maximal delay between peak velocities of opposing basal LV walls was measured using tissue Doppler echocardiography, as an index of LV dyssynchrony. With the initiation of RVP, LV dyssynchrony increased in some patients and decreased in others, as compared with intrinsic rhythm. The RVP-induced change in dyssynchrony inversely correlated with baseline dyssynchrony (r = -0.686, P = .010). After 28 ± 3.6 months, LV end-systolic volume (ESV) increased, and ejection fraction decreased (from 34 ± 12 to 40 ± 20 mL, P = .010 and from 65% ± 6% to 56% ± 11%, P < .001, respectively). The change in LV ESV was greater in patients with 60% or greater cumulative RVP (9.9 vs 0.08 mL, P = .027). Within this frequently paced group, the RVP-induced change in dyssynchrony correlated with the increase in LV ESV (r = 0.727, P = .026). Patients who had a 15% or greater increase in LV ESV had greater RVP-induced change in dyssynchrony (28.4 vs -7.8 milliseconds, P = .037).
  
  
  CONCLUSIONS
  Some patients with AV block experience an increase in LV dyssynchrony with RVP. Increased LV dyssynchrony predicts adverse LV remodeling during long-term follow-up.
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary. Electronic address: pap.paprobert@gmail.com.
authors.forename: Róbert
authors.initials: R
authors.lastname: Pap
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Gallardo
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: Dóra
authors.initials: D
authors.lastname: Rónaszéki
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: Gergely
authors.initials: G
authors.lastname: Ágoston
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: Vassil B
authors.initials: VB
authors.lastname: Traykov
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Sághy
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: Albert
authors.initials: A
authors.lastname: Varga
authors.affiliation: 2nd Department of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Forster
mesh_terms: D000368:Aged; D054537:Atrioventricular Block / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D018487:Ventricular Dysfunction, Left / Q000209:etiology* / Q000503:physiopathology; D020257:Ventricular Remodeling