Delay of left ventricular longitudinal expansion with diastolic dysfunction: impact on load dependence of e′ and longitudinal strain rate
Little, William C.
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The effect of diastolic dysfunction (DD) on the timing of left ventricular (LV) diastolic longitudinal and circumferential expansion and their load dependence is not known. This study evaluated the timing of the peak early diastolic LV inflow velocity (E), mitral annular velocity (e'), and longitudinal and circumferential global strain rates (SRE) in 161 patients in sinus rhythm. The intraventricular pressure difference (IVPD) from the left atrium to the LV apex was obtained using color M-mode Doppler data to integrate the Euler equation. The diastolic function was graded according to the guidelines. In normals (N = 57), E, e', longitudinal SRE, and circumferential SRE occurred nearly simultaneously during the IVPD. With DD (N = 104), e' and longitudinal SRE were delayed occurring after the IVPD (e': 18 +/- 23 msec, longitudinal SRE: 13 +/- 21 msec from the IVPD), whereas circumferential SRE (-8 +/- 28 msec) and E (-2 +/- 13 msec) were not delayed. The normal dependence of e' and longitudinal SRE on IVPD was reduced in DD; while the relation of circumferential SRE and E to IVPD were unchanged in DD. Thus, normally, the LV expands symmetrically during early diastole and both longitudinal and circumferential expansions are related to the IVPD. With DD, early diastolic longitudinal LV expansion is delayed, occurring after the IVPD and LV filling, resulting in their relative independence from the IVPD. In contrast, with DD, circumferential SRE and mitral inflow are not delayed and their normal relation to the IVPD is unchanged.