title: Defining the optimum upper heart rate limit during exercise: a study in pacemaker patients with heart failure.
abstract: OBJECTIVE
  There is no non-invasive method to determine the individual optimum of maximum exercise heart rate. Knowledge of this value is of particular interest in patients with structural heart disease who are prone to tachycardia intolerance. The purpose of this study was to define the optimal maximum heart rate using cardiopulmonary exercise testing and exercise Doppler echocardiography and to compare the results of both approaches.
  
  
  RESULTS
  In 49 pacemaker patients with chronotropic incompetence, the optimum upper heart rate limit was determined using cardiopulmonary exercise testing and exercise Doppler echocardiography. The optimum upper rate limit was given by the highest pacing rate which still produced an increase in oxygen consumption, or by that pacing rate which was linked to the lowest value for the Doppler-derived myocardial performance index. In patients with normal left ventricular ejection fraction (>or=55%) the optimum upper rate limit was 86% of age-predicted maximum heart rate, in patients with left ventriuclar dysfunction (ejection fraction <or=45%) it was 75% of the age-predicted maximum rate (P=0.004). The optimum upper rate limit, as defined by cardiopulmonary exercise testing and exercise Doppler echocardiography, were closely correlated (P<0.0001) with a mean deviation of 6+/-6 beats x min(-1).
  
  
  CONCLUSIONS
  Cardiopulmonary exercise testing and exercise Doppler echocardiography are valuable tools which help to determine the optimum upper rate limit in order to avoid excess heart rates in heart failure patients. The application of these methods is not limited to pacemaker patients but may be helpful in therapeutic interventions with chronotropic drugs.
authors.affiliation: Department of Internal Medicine, Universitätskliniken des Saarlandes, Homburg/Saar, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kindermann
authors.forename: B
authors.initials: B
authors.lastname: Schwaab
authors.forename: N
authors.initials: N
authors.lastname: Finkler
authors.forename: S
authors.initials: S
authors.lastname: Schaller
authors.forename: M
authors.initials: M
authors.lastname: Böhm
authors.forename: G
authors.initials: G
authors.lastname: Fröhlig
mesh_terms: D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D015150:Echocardiography, Doppler; D005080:Exercise Test / Q000379:methods*; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012016:Reference Values