title: Combining low-intensity and maximal exercise test results improves prognostic prediction in chronic heart failure.
abstract: OBJECTIVE
  This study investigated the combination of maximal and low-intensity exercise testing in predicting prognosis in chronic heart failure (CHF), using one single exercise test (two-step protocol).
  
  
  BACKGROUND
  Risk assessment based on any single factor has limited accuracy and reproducibility.
  
  
  METHODS
  Treadmill exercise testing was performed in 202 consecutive CHF patients (174 male; mean age 52 +/- 11 years) using "breath-by-breath" gas exchange monitoring. Oxygen uptake (VO(2)) kinetics were defined as oxygen deficit (DeltaVO(2) x time [rest to steady state] - Sigma VO(2) [rest to steady state]) and mean response time (MRT = oxygen-deficit/DeltaVO(2)). Peak VO(2) (VO(2)max) was defined as the highest VO(2). Mean follow-up was 873 +/- 628 days. The primary end point was cardiac mortality and the need for urgent heart transplantation.
  
  
  RESULTS
  Forty-four patients (22%) died and 15 (7%) were urgently transplanted. In both univariate and multivariate analyses, MRT >50 s was the most powerful predictor of the primary end point (hazard ratio [HR] 4.44), followed by predicted VO(2)max <50% (HR 3.50) and resting systolic blood pressure <105 mm Hg (HR 2.49, all p < 0.001). A majority (n = 130 [64%]) had one or none of these risk factors, with a one-year event rate of only 3%. Patients with two risk factors (n = 45 [22%]) were at medium risk (one-year event rate of 33%). Twenty-seven patients (13%) had all three risk factors, with a one-year event rate of 59%. The area under the curve, using the number of risk factors, was 0.86 +/- 0.04 for the primary end point at one year. These results were independent of medication, in particular, beta-blockade.
  
  
  CONCLUSIONS
  A combination of low-intensity and maximal exercise test results improves assessment of prognosis in patients with CHF.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University Hospital, Zürich, Switzerland.
authors.forename: Hans
authors.initials: H
authors.lastname: Rickli
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kiowski
authors.forename: Manuel
authors.initials: M
authors.lastname: Brehm
authors.forename: Daniel
authors.initials: D
authors.lastname: Weilenmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Schalcher
authors.forename: Alain
authors.initials: A
authors.lastname: Bernheim
authors.forename: Erwin
authors.initials: E
authors.lastname: Oechslin
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Brunner-La Rocca
mesh_terms: D000328:Adult; D002302:Cardiac Output; D023381:Endpoint Determination; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000601:surgery; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010101:Oxygen Consumption; D011379:Prognosis; D012372:ROC Curve; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume