Echocardiographic assessment of right ventricular contractile reserve in healthy subjects

Background: Exercise-induced increase in pulmonary artery systolic pressure (PASP) as a possible measure of right ventricular (RV) contractile reserve has been shown to predict survival in severe pulmonary hypertension. However, RV contractile reserve can also be measured by changes in stroke volume (SV), tricuspid annular plane systolic excursion (TAPSE), or tricuspid annular systolic velocity (S'). The limits of normal values and the functional significance of these changes in healthy subjects are not well known. Methods: In this prospective study, 90 healthy subjects (45 male, mean age 39 ± 13years) underwent exercise stress echocardiography with measurement of TAPSE, S', TAPSE/PASP, SV, and PASP at rest and peak exercise. Maximum and minimum normal values were reported for all indices. Results: Normal values of exercise-induced changes (Δ) were 4 to 10mm for TAPSE, 6 to 14cm/s for S', 12 to 57mm Hg for PASP, 0 to 96mL for SV, and −1.2 to 0mm/mm Hg for TAPSE/PASP. At peak exercise, women showed lower ΔTAPSE/PASP, ΔPASP, ΔS', and ΔSV, but higher TAPSE/PASP than men. Aging was associated with decreased ΔTAPSE/PASP, ΔTAPSE, ΔS', ΔPASP, and ΔSV. In addition, ΔS', ΔTAPSE/PASP, ΔPASP, and ΔSV, but not ΔTAPSE, were directly correlated with maximum workload. Conclusions: Our results provide age- and sex-related limits of normal for RV contractile reserve as assessed by exercise stress echocardiography and demonstrate that RV systolic function indices (PASP, TAPSE, S', and TAPSE/PASP) correlate with maximum exercise capacity.