Exercise Echocardiography Combined with Cardiopulmonary Exercise Testing in Small Children

Background: Exercise echocardiography in combination with cardiopulmonary exercise testing (CPET) allows for evaluation of cardiac function evaluated using echocardiography during physical exertion while at the same time measuring cardiopulmonary function. As heart rate can only be increased to maximal levels during true physical exercise this is the only method to evaluate cardiac function during maximal exercise while at the same time allowing for objectifying the extent of physical exertion. So far, exercise echocardiography is mainly limited to adults tall enough to fit on a tilt-recline ergometer.

Method: We evaluated 6 children (3 girls and 3 boys) after arterial switch operation or Kawasaki disease, below the required height for tilt-recline ergometers, for exercise echocardiography in combination with CPET on a treadmill. We used an adapted Bruce treadmill protocol. All Echocardiography assessments were undertaken with the child standing upright, bent slightly forward. The evaluations were undertaken before CPET, after the 4th and the 8th step, and directly as well as after 2 and 3 minutes after ending the exercise. The treadmill was stopped for echocardiography for 30 seconds.

Results: All children were able to perform the exercise tests up to maximal exertion. The CPET results are presented in the following table. Exercise echocardiography allowed for good image quality even for evaluating global longitudinal strain. Five children presented with normal cardiac function even at peak exercise. One child showed reduced cardiac function which worsened over the course of the CPET. A catheter investigation revealed stenosis of the right coronary artery.

Parameter	Mean ± standard deviation
(mL/kg/min)	48.0 ± 4.9
Peak RER	1.3 ± 0.1
Peak heart rate (beats/minute)	195 ± 8.6
Exercise time (min)	15.3 ± 1.8
Peak O2 pulse (mL/min)	6.7 ± 1.0

Conclusion: Exercise echocardiography in combination with cardiopulmonary exercise testing in children too small for being able to perform on a tilt-recline ergometer is feasible and safe. Image quality during upright echocardiography is very high and allows for the estimation of global longitudinal strain. This is a first study showing the possible inclusion of exercise echocardiography for evaluating coronary insufficiency in children during exertion.

Publication History

Article published online:
28 January 2023