title: Influence of stroke volume and exercise tolerance on peak oxygen pulse in patients with and without beta-adrenergic receptor blockers in patients with heart disease.
abstract: In a given individual, a consistent relationship exists between oxygen uptake (V˙O2) and heart rate (HR) during exercise. The quotient of V˙O2and HR (V˙O2/HR) is called the oxygen pulse (O2pulse), and its value is dependent on stroke volume (SV). However, it is difficult to believe that the O2pulse would indicate the SV when HR has been modified as with the use of beta-adrenergic receptor blockers (BB). Until now, the effect of BB on peak O2pulse has not been precisely studied. We tried to clarify the effect of BB on the relationship between O2pulse and SV.
  
  
  
  Of 699 consecutive heart disease subjects who performed cardiopulmonary exercise tests (CPX) from 2012 to 2014, we enrolled 430 subjects who had sinus rhythm and could perform CPX until exhaustion. One hundred and fifty-seven subjects were taking BB. SV was evaluated during CPX using impedance cardiography, and we compared the peak O2pulse with peak SV between patients without BB (Group A) and with BB (Group B).
  
  
  
  The HRs at rest and peak exercise in Group A were greater than those in Group B (74.4±13.0/min vs. 71.8±11.3/min, p<0.01, 134.9±21.7/min vs. 124.9±23.6/min, p<0.01, respectively). The regression line of the peak O2pulse against the peak SV was steeper in Group B than in Group A. When we divided the patients into two groups according to the average values of the peak SV and peak V˙O2, O2pulse/SV ratio in Group B above the average was greater than that in Group A, whereas it was similar in the two groups that were below average.
  
  
  
  We found that the increase in the O2pulse was disproportionately greater than the SV that was measured by impedance cardiography when a BB was used in patients with preserved SV and exercise tolerance.
authors.affiliation: Department of Medicine and Biological Science, Graduate School of Medicine, Gunma University School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Murata
authors.affiliation: Gunma Prefectural Cardiovascular Center, Department of Cardiology, Maebashi, Gunma, Japan. Electronic address: h-adachi@ops.dti.ne.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Adachi
authors.affiliation: Gunma Prefectural Cardiovascular Center, Department of Cardiology, Maebashi, Gunma, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Oshima
authors.affiliation: Department of Medicine and Biological Science, Graduate School of Medicine, Gunma University School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kurabayashi
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000009:adverse effects*; D000368:Aged; D002307:Cardiography, Impedance; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006331:Heart Diseases / Q000188:drug therapy / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D012146:Rest / Q000502:physiology; D013318:Stroke Volume / Q000187:drug effects* / Q000502:physiology
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: Beta-adrenergic receptor blocker; Cardiopulmonary exercise test; Oxygen pulse; Stroke volume