title: Immediate and chronic effects of AV-delay optimization in patients with cardiac resynchronization therapy.
abstract: BACKGROUND
  Acute changes of the AV-delay in CRT patients have a significant impact on hemodynamics. However, the chronic functional effects of AV-delay optimization have not been systematically examined despite of their potential role for chronic functional improvement.
  
  
  METHODS
  Therefore, in this study we investigated whether optimization of AV-delay in CRT patients as assessed by echocardiographic measurement of the velocity time integral of the left ventricular outflow tract (LVOT-VTI) chronically changes (1) echocardiographic parameters of systolic and diastolic left ventricular function, (2) walking distance in the 6-min walk test, (3) levels of NT-proBNP and (4) quality of life as assessed by a standard questionnaire. 33 patients underwent optimization of AV-delay 31+/-8 weeks after initiation of CRT. Follow up (FU) was conducted 43+/-5 days later.
  
  
  RESULTS
  E/Ea, the ratio of peak E-wave of mitral inflow and of TDI of the mitral annulus, significantly decreased immediately post-optimization (11+/-1 vs. 14+/-1 at baseline, p<0.05) and further decreased at FU (8+/-1, p<0.05 vs. immediately post-optimization) indicating improvement of diastolic function, while traditional parameters of diastolic function derived from pulse wave Doppler remained unchanged. There was a slight increase of LV-ejection fraction as assessed by echocardiography acutely after optimization (baseline: 25+/-2%, optimized: 28+/-1%, p<0.05), while LV-ejection fraction at FU did not differ from baseline. 6-min walk test improved from 449+/-17 m (baseline) to 475+/-17 m at FU (p<0.05). During this period NT-proBNP significantly decreased from 3193+/-765 ng/l to 2593+/-675 ng/l (p<0.05). Quality of life was unchanged at FU.
  
  
  CONCLUSIONS
  This study demonstrates for the first time chronic functional improvement due to AV-delay optimization in patients with CRT.
authors.affiliation: Department of Cardiology, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany. stefan_hardt@med.uni-heidelberg.de
authors.forename: Stefan E
authors.initials: SE
authors.lastname: Hardt
authors.forename: Said Hashem Fani
authors.initials: SH
authors.lastname: Yazdi
authors.forename: Alexander
authors.initials: A
authors.lastname: Bauer
authors.forename: Arthur
authors.initials: A
authors.lastname: Filusch
authors.forename: Grigorios
authors.initials: G
authors.lastname: Korosoglou
authors.forename: Alexander
authors.initials: A
authors.lastname: Hansen
authors.forename: Raffi
authors.initials: R
authors.lastname: Bekeredjian
authors.forename: Philipp
authors.initials: P
authors.lastname: Ehlermann
authors.forename: Andrew
authors.initials: A
authors.lastname: Remppis
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.forename: Helmut F
authors.initials: HF
authors.lastname: Kuecherer
mesh_terms: D000208:Acute Disease; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002908:Chronic Disease; D018619:Echocardiography, Doppler, Pulsed; D004562:Electrocardiography; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010138:Pacemaker, Artificial; D010446:Peptide Fragments / Q000097:blood*; D011336:Probability; D011788:Quality of Life; D013318:Stroke Volume; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain