title: Heart rate recovery after exercise is a predictor of mortality, independent of the angiographic severity of coronary disease.
abstract: OBJECTIVE
  We sought to determine whether abnormal heart rate recovery predicts mortality independent of the angiographic severity of coronary disease.
  
  
  BACKGROUND
  An attenuated decrease in heart rate after exercise, or heart rate recovery (HRR), has been shown to predict mortality. There are few data on its prognostic significance once the angiographic severity of coronary artery disease (CAD) is ascertained.
  
  
  METHODS
  For six years we followed 2,935 consecutive patients who underwent symptom-limited exercise testing for suspected CAD and then had a coronary angiogram within 90 days. The HRR was abnormal if < or =12 beats/min during the first minute after exercise, except among patients undergoing stress echocardiography, in whom the cutoff was < or =18 beats/min. Angiographic CAD was considered severe if the Duke CAD Prognostic Severity Index was > or =42 (on a scale of 0 to 100), which corresponds to a level of CAD where revascularization is associated with better long-term survival.
  
  
  RESULTS
  Severe CAD was present in 421 patients (14%), whereas abnormal HRR was noted in 838 patients (29%). There were 336 deaths (11%). Mortality was predicted by abnormal HRR (hazard ratio [HR] 2.5, 95% confidence interval [CI] 2.0 to 3.1; p < 0.0001) and by severe CAD (HR 2.0, 95% CI 1.6 to 2.6; p < 0.0001); both variables provided additive prognostic information. After adjusting for age, gender, standard risk factors, medications, exercise capacity, and left ventricular function, abnormal HRR remained predictive of death (adjusted HR 1.6, 95% CI 1.2 to 2.0; p < 0.0001); severe CAD was also predictive (adjusted HR 1.4, 95% CI 1.1 to 1.9; p = 0.008).
  
  
  CONCLUSIONS
  Even after taking into account the angiographic severity of CAD, left ventricular function, and exercise capacity, HRR is independently predictive of mortality.
authors.affiliation: Department of Cardiovascular Medicine, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Deepak P
authors.initials: DP
authors.lastname: Vivekananthan
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Blackstone
authors.forename: Claire E
authors.initials: CE
authors.lastname: Pothier
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lauer
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D017023:Coronary Angiography / Q000592:standards*; D003327:Coronary Disease / Q000145:classification / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D004452:Echocardiography / Q000379:methods / Q000592:standards*; D005080:Exercise Test / Q000379:methods / Q000592:standards*; D017079:Exercise Tolerance; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D020127:Recovery of Function; D012307:Risk Factors; D012720:Severity of Illness Index; D013318:Stroke Volume; D016019:Survival Analysis; D016277:Ventricular Function, Left