Feasibility of exercise stress echocardiography and myocardial response in patients with repaired congenital heart disease

Background Exercise stress echocardiography (ESE) can unmask ventricular dysfunction in asymptomatic patients with congenital heart disease (CHD), but its acquisition and interpretation is often challenging, and the method has not been validated in CHD. This study aimed to evaluate the feasibility of ESE using Doppler imaging and to assess myocardial response to exercise in patients with biventricular (BiV) and univentricular (UniV) circulation after CHD repair. Methods In this single-center prospective study, we recruited 55 participants (17 females), median age 14 years (8-22 years). Our analysis categorized participants in these three groups: with structurally normal hearts as controls (n = 21), with BiV circulation (n = 20) and with UniV circulation (n = 14). We acquired ESE images of the systemic ventricle including pulsed wave flow and spectral tissue Doppler imaging (TDI) of lateral free wall before and immediately after standard, symptom limited exercise tests on an electronically braked cycle ergometer. Results During ESE we obtained inflow E-wave and TDI systolic (S') and early diastolic (E') velocities in 93% to 100% of participants at rest and in 90% to 100% of participants post exercise. Feasibility to obtain Doppler imaging parameter was the same across study groups. The myocardial response to exercise was increase in heart rate (HR), S' and inflow E-wave velocity in all participants. Patients with BiV circulation had preserved ventricular function at rest. While patients with UniV circulation had low S', E', and E-wave velocities at rest in comparison to controls and to BiV group (all P <.001), both patients with BiV and UniV circulation showed significant increases in HR, S' velocity and inflow E-wave velocity post exercise, with magnitudes of these increases higher in controls than in the BiV and UniV group. The S' and E' velocities were strongly associated with lower percent predicted peak oxygen consumption VO2 (r(s) = 0.614 and r(s) = 0.64, respectively, both P <.001). Conclusion ESE with Doppler imaging is a practical noninvasive diagnostic method and sufficiently robust for the assessment of morphologic LV/systemic ventricles under exercise in patients after biventricular and univentricular CHD repair. Although patients with BiV and UniV circulation had both preserved myocardial response to exercise, the magnitude of this response was the lowest in patients with UniV circulation.