Normal left ventricular function consists of 2 interrelated processes. Systole comprises a coordinated interplay between fiber shortening, wall thickening, longitudinal shortening, and cardiac twist, which results in the generation of stroke volume. During diastole, which comprises relaxation and untwist, as well as contraction of the atrium, the normal ventricle relaxes and fills to an adequate end-diastolic volume at low pressure—thus optimizing stroke volume in the next systole.¹

The noninvasive assessment of systolic and diastolic function is a major undertaking of cardiologists, and in 2015, this assessment is usually performed with echocardiography. The assessment of systolic function, which began with M-mode echocardiography in the 1970s, now comprises both 2D and 3D echocardiography, as well as regional function assessment with speckle tracking. The assessment of diastolic function became routine in the 1980s, with the development of pulsed Doppler measurement of transmitral flow velocities: early (E) and late/atrial contraction (A) velocities and pulmonary venous flows.²