Patient selection: adult survivor of a childhood cancer
Exercise intolerance was defined as peak oxygen uptake in mL per min per kg < 85% of predicted.
Low cardiorespiratory fitness is a maximal aerobic capacity < 7.9 METS.
Predictors of exercise intolerance:
(1) abnormal global longitudinal peak systolic strain on speckle tracking of apical views at echocardiography (> 1.5 SD above mean for age, sex and vendor means)
(2) FEV1 < 80% of predicted
(3) isokinetic quadriceps strength while sitting that is 1 SD below mean for age and sex
(4) chronotropic incompetence (<80% of predicted for age and sex predicted heart rate reserve; an indicator of blunted autonomic response)
Significance:
(1) A patient with a cardiac cause of exercise intolerance may be at increased risk for heart failure.
(2) The pattern of underlying deficiencies is important for planning an effective exercise program.
Other factors to consider (not discussed):
(1) deconditioning
(2) comorbidities and frailty