Focused cardiac ultrasound identification of dynamic LV outflow tract obstruction

(A) A normal parasternal long-axis view such that when the aortic valve is open (ie, systole), the left ventricular outflow tract (asterisk) is also open (proposed mnemonic: open-open). (B) An abnormal parasternal long-axis view: with the aortic valve open (again identifying systole), there is systolic anterior motion of the mitral valve obstructing the left ventricular outflow tract and causing dynamic left ventricular outflow tract obstruction (mnemonic: open-closed).