title: Effects of atrioventricular conduction delay on the outcome of cardiac resynchronization therapy.
abstract: OBJECTIVE
  First-degree atrioventricular (AV) block in relation to the outcome of cardiac resynchronization therapy (CRT) has not been well examined.
  
  
  METHODS
  Patients who received a CRT defibrillator or pacemaker between January 2002 and September 2010 at Mayo Clinic were classified into 2 groups: normal PR interval and prolonged PR interval. Standard sensed (100 milliseconds) and paced (130 milliseconds) AV delay was programmed after CRT. Clinical presentations and echocardiography were assessed before CRT and at a median of 6 months after CRT.
  
  
  RESULTS
  The normal PR interval group (n=199) had greater improvements in heart failure functional class (mean [SD], 0.7 [0.8] vs 0.5 [0.9]; P=.03) and left ventricular ejection fraction (9.4% [12.4%] vs 5.9% [9.5%]; P=.007) than the prolonged PR group (n=204).
  
  
  CONCLUSIONS
  Compared with prolonged PR interval, the presence of normal PR interval was associated with a greater improvement in heart failure.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA; Cardiovascular Medicine, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Ying-Hsiang
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA; Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Jia-Hui
authors.initials: JH
authors.lastname: Wu
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Freddy
authors.initials: F
authors.lastname: Del Carpio Munoz
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Tracy
authors.initials: T
authors.lastname: Webster
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Brooke
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Wiste
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. Electronic address: ycha@mayo.edu.
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
mesh_terms: D000368:Aged; D054537:Atrioventricular Block / Q000401:mortality* / Q000517:prevention & control*; D058406:Cardiac Resynchronization Therapy / Q000401:mortality* / Q000706:statistics & numerical data*; D015897:Comorbidity; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008910:Minnesota / Q000453:epidemiology; D011379:Prognosis; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Atrioventricular block; Cardiac resynchronization; Dyssynchrony; Heart failure; PR interval; Survival