Appropriate heart rate during exercise in Fontan patients

Abstract

Objective:To evaluate heart rate against workload and oxygen consumption during exercise in Fontan patients.Method:Fontan patients (n = 27) and healthy controls (n = 25) underwent cardiopulmonary exercise testing with linear increase of load. Heart rate and oxygen uptake were measured during tests. Heart rate recovery was recorded for 10 minutes.Results:Heart rate at midpoint (140 ± 14 versus 153 ± 11, p < 0.001) and at maximal effort (171 ± 14 versus 191 ± 10 beats per minute, p < 0.001) of test was lower for patients than controls. Heart rate recovery was similar between groups. Heart rate in relation to workload was higher for patients than controls both at midpoint and maximal effort. Heart rate in relation to oxygen uptake was similar between groups throughout test. Oxygen pulse, an indirect surrogate measure of stroke volume, was reduced at maximal effort in patients compared to controls (6.6 ± 1.1 versus 7.5 ± 1.4 ml·beat−1·m−2, p < 0.05) and increased significantly less from midpoint to maximal effort for patients than controls (p < 0.05).Conclusions:Heart rate is increased in relation to workload in Fontan patients compared with controls. At higher loads, Fontan patients seem to have reduced heart rate and smaller increase in oxygen pulse, which may be explained by inability to further increase stroke volume and cardiac output. Reduced ability to increase or maintain stroke volume at higher heart rates may be an important limiting factor for maximal cardiac output, oxygen uptake, and physical performance.

Endurance training may improve exercise capacity, lung function and quality of life in Fontan patients

“…We studied heart rate response to increased load during exercise testing. 15 Heart rate at rest was similar between patients and controls but heart rate at midpoint of the test and at maximal effort was lower for Fontan patients than controls. Furthermore, heart rate in relation to workload was higher for patients than controls at mid and maximal effort (Figure 3).…”

“…Mean ± 1SD. p ‐values denote comparisons between groups 15 . Republished with permission from Cambridge University Press…”

“…Other studies [44][45][46] At maximal exercise testing, we found that Fontan patients had lower maximal heart rate and blood pressure, and lower oxygen saturation compared with healthy controls. 13,15 Apart from the haemodynamic limitations in the Fontan circulation, patients may also lack experience or motivation or have fear of complications or severe symptoms, in order to perform activities at higher intensities.…”

“…Data and discussions are centred around our own published studies [12][13][14][15][16] performed in 2010-2018 and are presented and used in illustrations. All children with Fontan palliation born between 1990 and 2005 in the Stockholm region, N = 53, were considered for participation.…”

Exercise Intolerance, Benefits, and Prescription for People Living With a Fontan Circulation: The Fontan Fitness Intervention Trial (F-FIT)—Rationale and Design

“…The observed diminished HR reserve (HRR) can be predominantly attributed to hemodynamic abnormalities (i.e., reduced preload) ( 56 ). However, during relative submaximal exercise intensities, the chronotropic response is appropriate or even higher compared to healthy control subjects ( 57 ).…”