Doppler Systolic Signal Void in @entity1121 : Apical XXXX and Severe Obstruction without Elevated Intraventricular  Velocities.

@entity1 @entity712 @entity1165 @entity1184 @entity3885 @entity2845 @entity439 @entity715 @entity1121
BACKGROUND: In @entity1 with @entity1121 ( @entity1121 ), @entity439 are associated with @entity1165 , @entity712 , apical @entity715 , and mortality. The cause of @entity439 remains unresolved, and there is controversy about prevalence and significance of mid-left ventricular (LV) obstruction, often present in these @entity1 . The aim of this study was to test the hypothesis that low velocities in @entity1 with @entity439 are due to near complete cessation of mid-LV flow, characteristically marked by a Doppler signal void. METHODS: This was a retrospective analysis of 39 @entity1 with @entity1121 with segmental @entity1184 of the mid left ventricle and complete systolic emptying at the mid-LV level. The severity of @entity3885 was evaluated by measuring the time during which cross-sectional mid-LV cavity area was <1  cm(2). Presence or absence of an LV Doppler midsystolic signal void was determined. RESULTS: Akinetic @entity439 were present in 21 @entity1 . The duration of two-dimensional mid-LV short-axis complete emptying was longer in @entity1 with @entity439 (194      45 vs 148      63  msec, P  =  .013), nearly 50% of systole. Midsystolic signal voids were seen only in @entity1 with @entity439 (P  <  .001), present in 86%. In @entity1 with @entity439 , there was a strong correlation between the duration of the systolic signal void and the proportion of systole with complete emptying <1  cm(2) (r  =  0.704; P  =  .001). Complete emptying <1  cm(2) for >= 38% of systole was associated with @entity439 (odds ratio, 9.35; P  <  .004). CONCLUSION: @entity1 with @entity2845 apical @entity439 @entity1121 have near complete cessation of flow across severe dynamic mid-LV obstruction for nearly 50% of systole. This explains how the adverse effects of obstruction may occur without high velocities on echocardiography.
