Relationship between Exercise Capacity and Ventilatory Equivalent for Carbon Dioxide in Patients with Stable Old Myocardial Infarction

Masahiro KIMURA; Masahiko HARAGUCHI; Kozo FUJII; Masahiko HARADA; Kaoru ONO; Makoto KUBO; Toshihiko TADA; Masako MATSUDA; Masunori MATSUZAKI

doi:10.1536/jhj.40.127

Masahiro KIMURA, Masahiko HARAGUCHI, Kozo FUJII, Masahiko HARADA, Kaoru ONO, Makoto KUBO, Toshihiko TADA, Masako MATSUDA, Masunori MATSUZAKI

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Masahiro KIMURA
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan
Masahiko HARAGUCHI
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan
Kozo FUJII
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan
Masahiko HARADA
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan
Kaoru ONO
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan
Makoto KUBO
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan
Toshihiko TADA
Saiseikai Yamaguchi General Hospital, Yamaguchi, Japan
Masako MATSUDA
School of Allied Health Sciences, Yamaguchi University, Ube, Japan
Masunori MATSUZAKI
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Ube, Japan

Keywords: Exercise tolerance test, Chronic heart failure, Oxygen consumption, Ventilatory equivalent for carbon dioxide, Airway obstruction

JOURNAL FREE ACCESS

1999 Volume 40 Issue 2 Pages 127-134

DOI https://doi.org/10.1536/jhj.40.127

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Abstract

The aim of the present study was to evaluate the relationship between exercise capacity and ventilatory response in patients with stable old myocardial infarction. We performed cardiopulmonary exercise test in 61 patients with stable old myocardial infarction and in 30 healthy men. Each subject exercised on a bicycle ergometer until exhaustion. Patients who had anginal pain or electrocardiographic ischemic changes during exercise were excluded. The patients were classified into three groups according to peakVO₂ achieved during exercise, using Weber's method: group A, peakVO₂≥21 ml/min/kg (n=4); group B, 14≤peakVO₂<21 ml/min/kg (n=45); and group C, peakVO₂<14 ml/min/kg (n=12). With progressive increases in VCO₂, VE increased linearly below the anaerobic threshold (AT) level. The slope of the linear regression line between VCO₂ and VE (SLOPE) was calculated in each subject. The mean SLOPE of the healthy men (group N) and groups A, B and C were 25.8±0.5, 25.1±0.5, 28.9±0.8 and 37.1±1.7 (×10^-3), respectively. Thus, the SLOPE was steeper in patients with lower peakVO₂. It is difficult to perform a maximal exercise tolerance test on patients with chronic heart failure to evaluate their exercise capacity. We can assess exercise capacity by the slope of the linear regression line between VCO₂ and VE (SLOPE) at the lower exercise level.

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