Two-slope ascending arm of the early trans-mitral flow velocity Doppler wave in patients with heart failure and preserved ejection fraction

Trans-mitral flow velocity (TMFV) examination is a standard echocardiographic measure for assessing diastolic function of the heart. Typically, the Doppler signal representing the early rapid filling phase of the left ventricle (LV), termed: E wave, is triangular. The ascending arm of the E wave (EWAA) represents blood accelerating into the LV from the left atrium (IA), whereas the descending arm reflects blood decelerating as the LV fills and resists further filling. The slope of EWAA is linear, starting at TMFV of zero cm/s (prior to mitral valve opening) and building to peak E wave value. The physical meaning of a single slope is that blood acceleration is constant with time. Little data exist regarding the significance of the shape of EWAA. It is hypothesized that in heart failure with preserved ejection fraction (HFPEF) the EWAA displays 2 slopes. A first steeper slope followed by a second less steep slope reaching peak E wave. The different slopes represent a change in the composition of driving forces propelling blood from LA to LV. It is hypothesized that the first steeper slope of EWAA represents a set of driving force including a force termed: diastolic suction, whereas in the second slope diastolic suction has already dissipated. This 2-slope phenomenon is not expected in healthy subjects because the assumed underlying mechanism is not operative. (C) 2014 Elsevier Ltd. All rights reserved.