Dobutamine stress echocardiography (DSE):
After six hours fasting, the dobutamine stress test was used to assess all echocardiographic parameters after dobutamine infusion [Started at 2.5 µg/kg/min, and increased gradually every 3 min and maximally to 40 µg/kg/min (Atropine was not given as it was unsafe and probably unnecessary in such age group)]. Dobutamine stress endpoints were taken with reaching the predicted target heart rate for age [85% (220 minus age in years)], starting symptoms (Dyspnea and or arrhythmia), or reaching 40 µg/kg/min dobutamine dose. Heart rate and blood pressure were recorded at every stage. Baseline and peak dose images were stored and compared offline. (8)
A normal response to dobutamine infusion was demarcated as a progressive increase in myocardial thickening and hyperdynamic wall motion as assessed by RV EF, RV GLS, and TAPSE from rest to peak dose dobutamine infusion (negative DSE). An abnormal response to dobutamine infusion was clarified as a reduction in myocardial thickening or wall motion at any stage of the dobutamine infusion compared with the previous stage (positive DSE). (8) Global contractile reserve was defined as improvement > 5% in RV EF, >2% in RV GLS, and/or to near normal parameter Z values in TAPSE. (8) Any change in cardiac function (improvement or worsening in RV EF, RV GLS, TAPSE), LVOT gradients, and severity of TR was reported.