Related Experiment Video
Updated: Aug 19, 2026
Integration of Brain Tissue Saturation Monitoring in Cardiopulmonary Exercise Testing in Patients with Heart Failure
Published on: October 1, 2019
Heart rate response to graded exercise correlates with aerobic and ventilatory capacity in patients with heart
Alessandro Vallebona1, Guido Gigli, Sandro Orlandi
1Department of Cardiology, Heart Failure Unit, Rapallo Hospital, Rapallo (Genoa), Italy. avallebona@as14.liguria.it
Background:
Autonomic dysfunction and reduced exercise tolerance are typical features of patients with congestive heart failure (CHF). Baro-chemoreflex balance and organ response may have a common role in conditioning exercise tolerance, ventilation, and chronotropic competence in patients with CHF.
Hypothesis:
We tested the hypothesis that there is a relationship between functional capacity and chronotropic competence to exercise in CHF.
Methods:
In all, 48 stable outpatients with CHF (age 65 +/- 10 years, 41 men, NYHA class 2.1 +/- 0, ejection fraction 31 +/- 7%, peak VO2 16 +/- 4 ml/kg/min) performed cardiopulmonary exercise testing (CPX). Heart rate (HR) response to exercise was assessed by the chronotropic index (CRI). The CRI was calculated by the following formula: CRI = peak HR - rest HR/220 - age - rest HR x 100 (normal value > 80%). The relationship of CRI to peak oxygen consumption (VO2) and ventilation/carbon dioxide production (VE/VCO2) ratio was examined. A group of 33 healthy controls underwent CPX as well.
Results:
The CRI correlated directly with peak VO2 (r = 0.638, p < 0.001) and inversely with VE/VCO2 (r = -0.492, p < 0.001) in patients with CHF. A CRI < 78% identified patients with CHF and a peak VO2 < 20 ml/kg/min, area under the receiver operating curve (AUROC): 0.76, 95% confidence interval (CI) 0.60-0.92. A CRI < 74% predicted exercise hyperventilation in CHF (AUROC: 0.71 for VE/VCO2 > 30, 95% CI 0.53-0.88). The CRI was not significantly related either to peak VO2 or to VE/VCO2 in the control group.
Conclusions:
In patients with mild to moderate CHF, CRI correlates with functional capacity. This relationship adds new data on pathophysiologic grounds and supports the routine incorporation of CRI into CPX interpretation.
Related Concept Videos
01:20Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:17Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:17Pathophysiology of Heart Failure
01:30Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
01:29Pathophysiology of Cardiac Performance