Hemodynamic changes at rest and during exercise in patients with aortic stenosis of varying severity

Treadmill exercise in apparently asymptomatic patients with moderate or severe aortic stenosis: relationship between cardiac index and revealed symptoms

“…Lee et al 27 showed normal increases in stroke volume on exercise measured invasively in patients with mild and moderate AS. However, in patients with symptomatic severe AS, stroke volume was significantly decreased at rest and on exercise.…”

Determinants and Functional Significance of Myocardial Perfusion Reserve in Severe Aortic Stenosis

“…output in severe AS is largely dependent on increased heart rate (26), which is associated with the development of impaired MPR in both patients (27) and experimental models of AS (28). The inability to increase blood flow to the myocardium is limited because vasodilation may already be near maximal (29), DPT will be limited further with increased heart rate, and there is a rapid increase in LV end-diastolic pressure (26), which further reduces the effective pressure gradient for perfusion. Patients unable to increase blood flow to the myocardium on exercise will likely develop subendocardial myocardial dysfunction (25,28), which will limit cardiac output and contribute to exercise intolerance.…”

Diagnostic usefulness of graded exercise testing in pediatric supraventricular tachycardia

“…Graded exercise testing has been considered as an integral part of the diagnostic evaluation of many children and young adults with cardiac disorders (24,25). In addition to the investigation of chest pain, there is an increasing number of applications for graded exercise testing in the pediatric population, including the evaluation of syncope and the hemodynamic assessment of left ventricular outflow tract obstruction (26)(27)(28)(29). Alterations in cardiac rhythm occur frequently with exercise and are of considerable importance in understanding a patient's functional and cardiovascular status, as well as prognosis, in various types of pediatric heart disease (16,30).…”