title: Effects of AV-delay optimization on hemodynamic parameters in patients with VDD pacemakers.
abstract: OBJECTIVE
  Atrioventricular (AV) delay optimization improves hemodynamics and clinical parameters in patients treated with cardiac resynchronization therapy and dual-chamber-pacemakers (PM). However, data on optimizing AV delay in patients treated with VDD-PMs are scarce. We, therefore, investigated the acute and chronic effects of AV delay optimization on hemodynamics in patients treated with VDD-PMs due to AV-conduction disturbances.
  
  
  METHODS
  In this prospective, single-center interventional trial, we included 64 patients (38 men, 26 women, median age: 77 (70-82) years) with implanted VDD-PM. AV-delay optimization was performed using a formula based on the surface electrocardiogram (ECG). Hemodynamic parameters (stroke volume (SV), cardiac output (CO), heart rate (HR), and blood pressure (BP)) were measured at baseline and follow-up after 3 months using impedance cardiography.
  
  
  RESULTS
  Using an ECG formula for AV-delay optimization, the AV interval was decreased from 180 (180-180) to 75 (75-100) ms. At baseline, AV-delay optimization led to a significant increase of both SV (71.3 ± 15.8 vs. 55.3 ± 12.7 ml, p < 0.001, for optimized AV delay vs. nominal AV interval, respectively) and CO (5.1 ± 1.4 vs. 3.9 ± 1.0 l/min, p < 0.001), while HR and BP remained unchanged. At follow-up, the improvement in CO remained stable (4.9 ± 1.3 l/min, p = 0.09), while SV slightly, but significantly, decreased (to 65.1 ± 17.6, p < 0.01).
  
  
  CONCLUSIONS
  AV-delay optimization in patients treated with VDD-PMs exhibits immediate beneficial effects on hemodynamic parameters that are sustained for 3 months.
authors.affiliation: Department of Internal Medicine II-Division of Cardiology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria, konstantin.krychtiuk@meduniwien.ac.at.
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Krychtiuk
authors.forename: Michael
authors.initials: M
authors.lastname: Nürnberg
authors.forename: Romana
authors.initials: R
authors.lastname: Volker
authors.forename: Linda
authors.initials: L
authors.lastname: Pachinger
authors.forename: Rudolf
authors.initials: R
authors.lastname: Jarai
authors.forename: Matthias K
authors.initials: MK
authors.lastname: Freynhofer
authors.forename: Johann
authors.initials: J
authors.lastname: Wojta
authors.forename: Kurt
authors.initials: K
authors.lastname: Huber
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Weiss
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*; D002302:Cardiac Output; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D013318:Stroke Volume; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome