title: Impairment of ventilatory efficiency in heart failure: prognostic impact.
abstract: BACKGROUND
  Impairment of ventilatory efficiency in congestive heart failure (CHF) correlates well with symptomatology and contributes importantly to dyspnea.
  
  
  RESULTS
  We investigated 142 CHF patients (mean NYHA class, 2.6; mean maximum oxygen consumption [VO(2)max], 15.3 mL O(2) x kg(-1) x min(-1); mean left ventricular ejection fraction [LVEF], 27%). Patients were compared with 101 healthy control subjects. Cardiopulmonary exercise testing was performed, and ventilatory efficiency was defined as the slope of the linear relationship of V(CO(2)) and ventilation (VE). Results are presented in percent of age- and sex-adjusted mean values. Forty-four events (37 deaths and 7 instances of heart transplantation, cardiomyoplasty, or left ventricular assist device implantation) occurred. Among VO(2)max, NYHA class, LVEF, total lung capacity, and age, the most powerful predictor of event-free survival was the VE versus V(CO(2)) slope; patients with a slope </=130% of age- and sex-adjusted normal values had a significantly better 1-year event-free survival (88.3%) than patients with a slope >130% (54.7%; P<0.001).
  
  
  CONCLUSIONS
  The VE versus V(CO(2)) slope is an excellent prognostic parameter. It is easier to obtain than parameters of maximal exercise capacity and is of higher prognostic importance than VO(2)max.
authors.affiliation: Medizinische Klinik und Poliklinik I, Universitätsklinikum Charité, Arbeitsgruppe Medizinische Biometrie, Humboldt-Universität zu Berlin, Berlin, Germany. franz-xaverk@ukb.de
authors.forename: F X
authors.initials: FX
authors.lastname: Kleber
authors.forename: G
authors.initials: G
authors.lastname: Vietzke
authors.forename: K D
authors.initials: KD
authors.lastname: Wernecke
authors.forename: U
authors.initials: U
authors.lastname: Bauer
authors.forename: C
authors.initials: C
authors.lastname: Opitz
authors.forename: R
authors.initials: R
authors.lastname: Wensel
authors.forename: A
authors.initials: A
authors.lastname: Sperfeld
authors.forename: S
authors.initials: S
authors.lastname: Gläser
mesh_terms: D000328:Adult; D000368:Aged; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000097:blood / Q000503:physiopathology*; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010100:Oxygen / Q000097:blood; D010807:Physical Endurance; D011379:Prognosis; D016016:Proportional Hazards Models; D012119:Respiration; D016019:Survival Analysis
chemical_list: D010100:Oxygen