title: Impact of right ventricular pacing on three-dimensional global left ventricular dyssynchrony in children and young adults with congenital and acquired heart block associated with congenital heart disease.
abstract: The aim of this study was to determine the effect of long-term right ventricular pacing on left ventricular (LV) mechanical dyssynchrony in children and young adults with congenital and acquired heart block. Eighteen patients aged 19 +/- 7 years with congenital heart block (group I), 9 aged 21 +/- 11 years with acquired heart block after congenital heart surgery (group II), and 15 healthy control subjects (group III) were studied. The LV volumes, ejection fractions, and systolic dyssynchrony index (SDI) values, as determined using 3-dimensional echocardiography, were compared among groups. Groups I (6.68 +/- 2.44%) and II (9.43 +/- 4.44%) had significantly greater SDI values than group III (3.88 +/- 0.63%) (p = 0.011 and p <0.001, respectively). The prevalence of LV mechanical dyssynchrony (SDI >5.14%, mean + 2 SDs of controls) in groups I and II was 72% and 67%, respectively. In 27 patients with right ventricular pacing, LV SDI values were correlated negatively with the LV ejection fractions (r = -0.74, p <0.001). The times to minimum regional volume were significantly longer in lateral, posterior, and inferior segments in group I and septal and inferior segments in group II compared to those in group III (p <0.05). Compared to patients without LV dyssynchrony, patients with LV dyssynchrony had lower LV ejection fractions (p <0.001), had shorter RR intervals (p <0.001), and tended to have dual-chamber pacing (p = 0.088) but had similar durations of pacing, QRS durations, and positions of pacing wires (epicardial vs endocardial). In conclusion, permanent right ventricular pacing in childhood has a negative effect on LV systolic function through the induction of mechanical dyssynchrony, the magnitude and pattern of which differ between congenital and acquired heart block.
authors.affiliation: Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong, China; Shanghai Children's Medical Center, Shanghai, China.
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Hong
authors.forename: Tak-cheung
authors.initials: TC
authors.lastname: Yung
authors.forename: Kin-shing
authors.initials: KS
authors.lastname: Lun
authors.forename: Sophia Jessica
authors.initials: SJ
authors.lastname: Wong
authors.forename: Yiu-fai
authors.initials: YF
authors.lastname: Cheung
mesh_terms: D000293:Adolescent; D002304:Cardiac Pacing, Artificial; D002648:Child; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006327:Heart Block / Q000151:congenital / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000628:therapy*; D055815:Young Adult