“…Reported values for the mean peak heart rate ranged from 142.2 AE 24.8 bpm 17 to 173.5 AE 16.0 bpm 26 (Table 1). Multiple studies reported that, compared with healthy controls, paediatric Fontan patients demonstrated significantly diminished peak stroke volume, 26 peak heart rate, 17,18,21,24,28 maximal heart rate, 23,29,30 heart rate gradient, 17 maximal heart rate response, 28,31 maximal stroke index, 23 stroke index response, 23 O 2 pulse, 30 and exercising O 2 saturation. 17 Two studies reported significantly decreased submaximal heart rate response, 28,31 and it was suggested by Banks et al 28 that paediatric Fontan patients may experience enhanced submaximal exercise efficiency relative to healthy individuals.…”