title: Cardiac output response to exercise in chronic cardiac failure patients.
abstract: The purpose of this study was to investigate the precise pattern of stroke volume (SV) response during exercise in patients with chronic heart failure (CHF) compared with age-matched controls. Fourteen patients with CHF and 7 controls performed symptom-limited bicycle exercise testing with respiratory gas exchange measurement. Patients were classified into group A (n = 7) with peak VO2 ≥ 18.0 mL/kg/minute and group B (n = 7) with peak VO2 < 18.0 mL/kg/ minute. SV and cardiac output (CO) were continuously measured during exercise using a novel thoracic impedance method (Physioflow). CO and SV were lower in the group B patients than those in controls at peak exercise [CO: 11.3 ± 1.0 (SE) versus 15.6 ± 0.9 L/minute, P < 0.05, SV: 89 ± 6 versus 110 ± 6 mL, P < 0.05]. SV reached its peak levels during submaximal exercise and remained close to the peak value until peak exercise in 6 of 7 group B patients (86%). On the other hand, it progressively increased until peak exercise in 6 of 7 controls (86%) and 5 of 7 group A patients (71%). In all subjects, CO at peak exercise was more closely correlated with SV at peak exercise (r = 0.86, P < 0.001) than with peak heart rate (r = 0.69, P < 0.001). CHF patients with impaired exercise capacity had attenuated increment of CO during exercise, and SV reached its peak levels during submaximal exercise.
authors.affiliation: Cardiovascular Department of Internal Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Taira
authors.initials: T
authors.lastname: Fukuda
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Miwa
authors.initials: M
authors.lastname: Kurano
authors.forename: Haruhito
authors.initials: H
authors.lastname: Takano
authors.forename: Haruko
authors.initials: H
authors.lastname: Iida
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Morita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamashita
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Hirata
authors.forename: Ryozo
authors.initials: R
authors.lastname: Nagai
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D002302:Cardiac Output / Q000502:physiology*; D002307:Cardiography, Impedance; D016022:Case-Control Studies; D002908:Chronic Disease; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology