title: Noninvasive measurement of atrial contribution to the cardiac output in children and adolescents with congenital complete atrioventricular block treated with dual-chamber pacemakers.
abstract: The contribution of atrial contraction to cardiac output (CO) has been the subject of extensive research but has yet to be quantified adequately in children and adolescents. Patients with third-degree atrioventricular (AV) block treated with pacemakers (PMs) are ideal candidates to assess the atrial contribution to CO by repeated measurements in single-chamber pacing mode (VVIR) and dual-chamber pacing mode (DDD/VDD). Hemodynamic measurements in children are often complicated by technical restrictions, but more recently a noninvasive method involving inert gas rebreathing has become available, which is an excellent tool for this age group. We examined 10 patients (6 female patients, mean age 14.5 ± 2.5 years, range 11 to 18) with congenital complete AV block treated with dual-chamber PM. Using an inert gas rebreathing device (Innocor) we measured CO in DDD/VDD with optimized AV delays. Devices were subsequently set to VVIR with matched heart rates and after 20 minutes the CO measurement was repeated. Mean CO of 6.4 ± 1.8 L/min was significantly higher in DDD/VDD than in VVIR, where it averaged 5.2 ± 1.4 L/min (p <0.001). Fractional increase of CO gained through sequential ventricular contraction was 18% (p <0.001). In VVIR, 8 patients reported PM-related symptoms. In conclusion, our data strongly suggest that pediatric patients with congenital complete AV block may benefit from AV synchrony with respect to hemodynamics and tolerability. Therefore, preferred use of DDD/VDD with optimized AV conduction delays should be considered.
authors.affiliation: Department of Pediatric Cardiology, University Hospital of Vienna, Vienna, Austria.
authors.forename: Jakob
authors.initials: J
authors.lastname: Hauser
authors.forename: Ina
authors.initials: I
authors.lastname: Michel-Behnke
authors.forename: Katarina
authors.initials: K
authors.lastname: Zervan
authors.forename: Christiane
authors.initials: C
authors.lastname: Pees
mesh_terms: D000293:Adolescent; D002302:Cardiac Output; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D002648:Child; D005260:Female; D006327:Heart Block / Q000151:congenital / Q000628:therapy; D006801:Humans; D008297:Male; D016896:Treatment Outcome