Cardiopulmonary exercise testing combined with stress echocardiography for the evaluation of myocardial dysfunction in children at risk

Aims In paediatric cardiology stress echocardiography is rarely used, even though it is an established tool for investigating myocardial insufficiency which represents a threat in children after arterial switch operation (ASO) or Kawasaki disease (KD). This study combines stress echocardiography with cardiopulmonary exercise testing (CPET) for evaluating these children. Methods: We recruited former patients from our database after ASO or KD. All undertook a CPET either on a tilt-recline ergometer or on a treadmill with intermittent echocardiography with strain measurements. In addition to the standard cardiopulmonary exercise parameters the behaviour of the O ₂ pulse before and after the end of exercise was evaluated. Results: 43 children, adolescents and adults (21 ASO mean age 14.7, 10 KD aged 15.0, and 13 controls aged 15.3 years) participated in this study. The patients after ASO showed a significantly lower peak cardiopulmonary function (\(\:\dot{V}{O}_{2}peak\): 39.6 vs 45.9 ml/kg/min) as well as a lower first ventilatory threshold (VT1) in percent of \(\:\dot{V}{O}_{2}peak\) (45.7 vs. 54%). The only other significant difference was a slower decline of the O ₂ pulse following the end of exercise. The strain values were normal. The patients undertook significantly less sport. Conclusion: The lower \(\:\dot{V}{O}_{2}peak\) in combination with the lower VT1 observed in the ASO group point to a lower cardiopulmonary function with poor endurance. In combination with the slower recovery of the O2pulse after exercise this could point to an impairment in cardiac output. Interestingly this was not true for the KD patients even when giant aneurysms were present.