Ventricular myocardial response to exercise in patients with Fontan circulation

Background Exercise stress echocardiography has been used to assess myocardial reserve in various heart diseases. This study examined the ventricular myocardial response to exercise in Fontan patients using exercise stress echocardiography. Methods Twenty-five Fontan patients and 19 control subjects underwent semi-supine bicycle exercise stress echocardiography in this prospective, single-center, cross-sectional study. Pulsed-wave Doppler tissue imaging peak systolic (s') and diastolic (e') velocities, longitudinal strain and systolic strain rate, and early diastolic strain rate data at rest and at peak exercise were obtained for the systemic ventricle. The myocardial reserve of functional parameters was calculated as the difference between peak exercise and rest. Results Inter- and intra-observer reliability were both high for exercise stress echocardiography measurements. Compared with controls, Fontan patients had significantly lower s', e', longitudinal systolic strain and strain rate, and early diastolic longitudinal strain rate at rest and at peak exercise as well as reduced myocardial reserve. Conclusions Fontan patients have markedly reduced myocardial reserve during exercise. The use of exercise stress echocardiography assessment may improve the clinical management of Fontan patients.