Alteration of Left Ventricular Endocardial Function by Intracavitary High-Power Ultrasound Interacts With Volume, Inotropic State, and al-Adrenergic Stimulation

Background. High-power intracavitary ultrasound abbreviates left ventricular (LV) ejection duration, thereby decreasing mechanical LV performance, presumably by selective impairment of endocardial endothelial function. Methods and Results. Effects of ultrasound were evaluated in the ejecting LV of anesthetized, open-chest dogs under different conditions of LV volume and contractile state and after mild selective al-adrenergic stimulation. LV pressures, left atrial pressures, and regional segment lengths were measured in anterior and posterior midwall. A cylindrical ultrasound probe (0.9 MHz, 25 W) mounted