title: The arterial baroreflex effectiveness index in risk stratification of chronic heart failure patients who are candidates for cardiac resynchronization therapy.
abstract: BACKGROUND
  Baroreflex function is an independent marker of prognosis in heart failure (HF). However, little is known about its relation to response to cardiac resynchronization therapy (CRT). The aim of this study is to assess arterial baroreflex function in HF patients who are candidates for CRT.
  
  
  METHODS
  The study population consisted of 25 patients with indication for CRT, aged 65±10 years, NYHA functional class ≥III in 52%, QRS width 159±15 ms, left ventricular ejection fraction (LVEF) 29±5%, left ventricular end-systolic volume (LVESV) 150±48 ml, B-type natriuretic peptide (BNP) 357±270 pg/ml, and peak oxygen consumption (peak VO2) 18.4±5.0 ml/kg/min. An orthostatic tilt test was performed to assess the baroreflex effectiveness index (BEI) by the sequence method. This group was compared with 15 age-matched healthy individuals.
  
  
  RESULTS
  HF patients showed a significantly depressed BEI during tilt (31±12% vs. 49±18%, p=0.001). A lower BEI was associated with higher BNP (p=0.038), lower peak VO2 (p=0.048), and higher LVESV (p=0.031). By applying a cut-off value of 25% for BEI, two clusters of patients were identified: lower risk cluster (BEI >25%) QRS 153 ms, LVESV 129 ml, BNP 146 pg/ml, peak VO2 19.0 ml/kg/min; and higher risk cluster (IEB ≤25%) QRS 167 ms, LVESV 189 ml, BNP 590 pg/ml, peak VO2 16.2 ml/kg/min.
  
  
  CONCLUSIONS
  Candidates for CRT show depressed arterial baroreflex function. Lower BEI was observed in high-risk HF patients. Baroreflex function correlated closely with other clinical HF parameters. Therefore, BEI may improve risk stratification in HF patients undergoing CRT.
authors.affiliation: Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal. Electronic address: jserodio@campus.ul.pt.
authors.forename: João
authors.initials: J
authors.lastname: Fernandes Serôdio
authors.affiliation: Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal; Department of Cardiology, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Mário
authors.initials: M
authors.lastname: Martins Oliveira
authors.affiliation: Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Matoso Laranjo
authors.affiliation: Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Tavares
authors.affiliation: Department of Cardiology, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Silva Cunha
authors.affiliation: Department of Cardiology, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Abreu
authors.affiliation: Department of Cardiology, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Luísa
authors.initials: L
authors.lastname: Branco
authors.affiliation: Department of Cardiology, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Sandra
authors.initials: S
authors.lastname: Alves
authors.affiliation: Institute of Physiology, Faculty of Medicine, University of Lisbon, Lisbon, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Rocha
authors.affiliation: Department of Cardiology, Santa Marta Hospital, Lisbon, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Cruz Ferreira
mesh_terms: D000368:Aged; D017704:Baroreflex; D058406:Cardiac Resynchronization Therapy; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain; D018570:Risk Assessment; D013318:Stroke Volume; D016896:Treatment Outcome
chemical_list: D020097:Natriuretic Peptide, Brain
keywords: Arterial baroreflex; Cardiac resynchronization therapy; Heart failure; Insuficiência cardíaca; Reflexo barorrecetor arterial; Ressincronização cardíaca