Moderate-dose @entity452 maximizes left ventricular contractile response during XXXX stress echocardiography in @entity1 .

@entity1 @entity452 @entity26 @entity67 @entity1642
BACKGROUND: Assessment of ventricular contractile reserve by @entity452 stress echocardiography (DSE) may be a powerful tool for detection of subclinical @entity67 , however, the hemodynamic dose-response relationship during DSE in @entity1 has not been established. METHODS: To characterize changes in hemodynamics and ventricular contractility during DSE in @entity1 , 26 @entity1 (age 8.3 +/- 4.8 years; 17 male/9 female) with normal resting left-ventricular function underwent DSE. @entity1 with abnormal wall motion at rest or during DSE, or rejection were excluded. Left ventricular M-mode echocardiography and carotid pulse tracings were obtained at each stage for calculation of shortening fraction, velocity of circumferential fiber shortening (VCFc), and end-systolic @entity1642 ( @entity1642 ). Contractility was expressed as the difference between actual and predicted VCFc for measured @entity1642 . Dose-response curves for shortening fraction, VCFc, @entity1642 , and contractility (the difference between actual and predicted VCFc for measured @entity1642 ) were obtained. RESULTS: Stepwise changes in contractility, systolic blood pressure, @entity1642 , and left ventricular shortening fraction were observed at doses up to, but not beyond, 20 microg/kg/min. Increases in double product were observed at doses up to 30 microg/kg/min. CONCLUSIONS: DSE at a @entity452 dose of 20 microg/kg/min is optimal to fully assess contractile reserve in @entity1 . Lesser doses may provide insufficient stress, whereas higher doses may incur unnecessary increases in myocardial @entity26 consumption and side effects.
