title: [Asynchronism and right ventricular pacing].
abstract: In patients with congenital heart block (CHB), dual-chamber pacing restores physiological heart rate and atrio-ventricular synchronization. However, patients with narrow QRS junctional escape rhythm may be deleteriously affected by long-term, permanent, apical ventricular pacing. We assessed the impact of apical ventricular pacing on echocardiographic ventricular dyssynchrony and hemodynamic parameters.
  
  
  METHODS
  Fourteen CHB adults (23 +/- years, 58% male), with a DDD transvenous pacemaker and a junctional escape rhythm (QRS<120 ms) before implantation, were studied. Echocardiography coupled with tissue Doppler imaging (TDI) and Strain rate was performed in spontaneous rhythm (VVI mode 30/mn) and during atrio-synchronized ventricular pacing.
  
  
  RESULTS
  The heart rate (43 +/- 09 vs 68 +/- 07: p<0.01), cardiac output (2.9 +/- 0.7 vs 3.7 +/- 0.6 L/min) and left ventricular filling time (325 +/- 38 vs 412 +/- 51 ms; p<0.01) were significantly less in the escape spontaneous rhythm compared with atrio-ventricular synchronized apical pacing. However, interventricular dyssynchrony (28 +/- 12 vs 59 +/- 25 ms, p<0.05), intra-left ventricular dyssynchrony (36 +/- 11 vs 57 +/- 29 ms; p<0.05), extent of left ventricular myocardium displaying delayed longitudinal contraction (26 +/- 10 vs 39 +/- 17%: p<0.05) were significantly less in the escape rhythm compared with paced rhythm.
  
  
  CONCLUSIONS
  Once implanted with a DDD pacemaker, CHB patients present with increased cardiac output secondary to the restoration of physiological heart rate and improved diastolic function. However, the apical site is not optimal, as it creates detrimental ventricular dyssynchrony in patients with previous nearly physiological ventricular activation. Alternative pacing sites should be investigated.
authors.affiliation: Hôpital cardiologique du Haut-Lévêque, service des maladies cardiovasculaires congénitales de l'enfant et de l'adulte, Pessac. jean-benoit.thambo@chu-bordeaux.fr
authors.forename: J B
authors.initials: JB
authors.lastname: Thambo
authors.forename: P
authors.initials: P
authors.lastname: Bordachar
authors.forename: S
authors.initials: S
authors.lastname: Lafitte
authors.forename: D
authors.initials: D
authors.lastname: Crepin
authors.forename: S
authors.initials: S
authors.lastname: Garrigue
authors.forename: S
authors.initials: S
authors.lastname: Reuter
authors.forename: R
authors.initials: R
authors.lastname: Roudaut
authors.forename: M
authors.initials: M
authors.lastname: Haïssaguerre
authors.forename: J
authors.initials: J
authors.lastname: Clementy
authors.forename: M
authors.initials: M
authors.lastname: Jimenez
mesh_terms: D000328:Adult; D002302:Cardiac Output; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003971:Diastole; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000151:congenital*; D006339:Heart Rate; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D016896:Treatment Outcome; D016277:Ventricular Function, Left