Use of maximal bicycle exercise testing with respiratory gas analysis to assess exercise performance in patients with congestive heart failure secondary to coronary artery disease or to idiopathic dilated cardiomyopathy
Abstract
Analysis of respiratory gases during maximal treadmill exercise testing has been used in patients with congestive heart failure (CHF) to detect the lactate threshold, presumed to reflect the onset of skeletal muscle underperfusion, and maximal oxygen consumption (VO2), the point at which VO2 plateaus with increasing work due to exhaustion of peripheral oxygen delivery capacity. To determine if this approach is also useful during maximal bicycle exercise testing, ventilatory, hemodynamic and systemic lactate responses to bicycle exercise were measured in 48 patients with CHF. Ventilatory responses also were assessed in 12 normal subjects. Exercise increased VO2 to 24.8 +/- 3.9 ml/min/kg in normal subjects and 13.9 +/- 3.7 ml/min/kg in patients with CHF (p less than 0.001). In all but 1 patient the VO2 increment over the last 3 minutes of exercise was comparable to that in normal subjects exercising over identical work times, suggesting that maximal VO2 was not achieved. Moreover, in patients who exercised for less than 6 minutes, a ventilatory lactate threshold could not be identified. In the 33 patients who exercised longer, a ventilatory lactate threshold was identified in 31 and correlated well (r = 0.81) with blood lactate t...Continue Reading
References
Citations
Improvement in exercise capacity after correction of anemia in patients with end-stage renal failure
Related Concepts
Related Feeds
Cardiovascular Diseases: Risk Factors
Cardiovascular disease is a significant health concern. Risk factors include hypertension, obesity, dyslipidemia and smoking. Women who are postmenopausal are at an increased risk of heart disease. Here is the latest research for risk factors of cardiovascular disease.
Cardiomyopathy
Cardiomyopathy is a disease of the heart muscle, that can lead to muscular or electrical dysfunction of the heart. It is often an irreversible disease that is associated with a poor prognosis. There are different causes and classifications of cardiomyopathies. Here are the latest discoveries pertaining to this disease.