scholarly journals Cross sectional early mitral flow velocity profiles from colour Doppler.

Heart ◽  
1989 ◽  
Vol 62 (3) ◽  
pp. 177-184 ◽  
Author(s):  
S O Samstad ◽  
H G Torp ◽  
D T Linker ◽  
O Rossvoll ◽  
T Skjaerpe ◽  
...  
Circulation ◽  
1992 ◽  
Vol 86 (3) ◽  
pp. 748-755 ◽  
Author(s):  
S O Samstad ◽  
O Rossvoll ◽  
H G Torp ◽  
T Skjaerpe ◽  
L Hatle

1994 ◽  
Vol 24 (2) ◽  
pp. 532-545 ◽  
Author(s):  
W.Yong Kim ◽  
Thue Bisgaard ◽  
Sten L. Nielsen ◽  
Jens K. Poulsen ◽  
Erik M. Pedersen ◽  
...  

Heart ◽  
2020 ◽  
Vol 106 (15) ◽  
pp. 1176-1182
Author(s):  
Timothy C Tan ◽  
Maria Carmo Pereira Nunes ◽  
Mark Handschumacher ◽  
Octavio Pontes-Neto ◽  
Yong-Hyun Park ◽  
...  

ObjectiveCardioembolic (CE) stroke carries significant morbidity and mortality. Left atrial (LA) size has been associated with CE risk. We hypothesised that differential LA remodelling impacts on pathophysiological mechanism of major CE strokes.MethodsA cohort of consecutive patients hospitalised with ischaemic stroke, classified into CE versus non-CE strokes using the Causative Classification System for Ischaemic Stroke were enrolled. LA shape and remodelling was characterised by assessing differences in maximal LA cross-sectional area (LA-CSA) in a cohort of 40 prospectively recruited patients with ischaemic stroke using three-dimensional (3D) echocardiography. Flow velocity profiles were measured in spherical versus ellipsoidal in vitro models to determine if LA shape influences flow dynamics. Two-dimensional (2D) LA-CSA was subsequently derived from standard echocardiographic views and compared with 3D LA-CSA.ResultsA total of 1023 patients with ischaemic stroke were included, 230 (22.5%) of them were classified as major CE. The mean age was 68±16 years, and 464 (45%) were women. The 2D calculated LA-CSA correlated strongly with the LA-CSA measured by 3D in both end-systole and end-diastole. In vitro flow models showed shape-related differences in mid-level flow velocity profiles. Increased LA-CSA was associated with major CE stroke (adjusted relative risk 1.10, 95% CI 1.04 to 1.16; p<0.001), independent of age, gender, atrial fibrillation, left ventricular ejection fraction and CHA2DS2-VASc score. Specifically, the inclusion of LA-CSA in a model with traditional risk factors for CE stroke resulted in significant improvement in model performance with the net reclassification improvement of 0.346 (95% CI 0.189 to 0.501; p=0.00001) and the integrated discrimination improvement of 0.013 (95% CI 0.003 to 0.024; p=0.0119).ConclusionsLA-CSA is a marker of adverse LA shape associated with CE stroke, reflecting importance of differential LA remodelling, not simply LA size, in the mechanism of CE risk.


2002 ◽  
Vol 2002.6 (0) ◽  
pp. 107-108
Author(s):  
Masanori Nakamura ◽  
Shigeo Wada ◽  
Taisei Mikami ◽  
Akira Kitabatake ◽  
Takeshi Karino

1995 ◽  
Vol 8 (3) ◽  
pp. 353
Author(s):  
Arzu Ilercil ◽  
Anna Maria Municino ◽  
Jose Santiago ◽  
Ying Zhu ◽  
Myung-Ho Lee ◽  
...  

1995 ◽  
Vol 268 (1) ◽  
pp. H25-H32 ◽  
Author(s):  
C. Alonso ◽  
A. R. Pries ◽  
O. Kiesslich ◽  
D. Lerche ◽  
P. Gaehtgens

Velocity profiles of human blood flowing through vertical and horizontal glass tubes (25–100 microns ID) were measured as a function of time following a sudden reduction of wall shear stress (tau w) from a high value to values ranging from 2 to 100 mPa. Cell velocities at various radial positions were determined off-line from video recordings by digital image analysis. In vertical tubes, symmetric velocity profiles were obtained that developed increasing bluntness with time, particularly at lower tau w and in smaller tubes. In horizontal tubes, velocity profiles developed strong asymmetry as a function of time. Red blood cell (RBC) sedimentation was associated with uniform low flow velocities in the concentrating cell sediment, whereas faster flow and almost parabolic profiles were observed in the supernatant plasma region. Calculations of effective blood viscosity showed a decrease with time at low tau w in vertical tubes but an increase in horizontal tubes. The differences between profile shape and effective viscosity in vertical and horizontal tubes disappeared at tau w > 50 mPa. These findings are related to the cross-sectional distribution of RBC, which depends on RBC aggregation and sedimentation.


2021 ◽  
Vol 8 (32) ◽  
pp. 3018-3022
Author(s):  
Sadhu Nagamuneiah ◽  
Gandikota Venkata Prakash ◽  
Sabitha P ◽  
Jandla Bhulaxmi ◽  
Dintyala Venkata S.S.Dintyala Venkata S.S. Mythri ◽  
...  

BACKGROUND Chronic arterial insufficiency (CAI) results in stenotic-occlusive disease of vascularized arterial disorders of tissues and organs. CAI of the lower extremities represents a significant medical and socio-economic problem due to a high incidence of morbidity, invalidity and mortality. METHODS A cross sectional analytical study was conducted in a group of 100 patients, admitted at the Vascular Department of the Sri Venkateshwara Ramnaraian Ruia Government General Hospital, Tirupati during the period from September 2018 to August 2019, with evident symptoms and signs of different stages of lower extremities CAI verified by ultrasonography. In patients with lower extremity disorder of tissue arterial capillaries, SpO2 was determined by pulse oximetry. CAI of the lower extremity was determined on the basis of clinical findings and colour Doppler duplex scan echo sonography results. Using the conventional method (single-gate) and colour Doppler duplex scan (multi-gate), the presence and localization of stenosis, the segmental predominance (with multisegmental forms) and the degree of progression of stenotic-occlusive lesions were verified. RESULTS Results Using pulse oximetry, depending on the of stage of lower extremities CAI, we revealed a considerable difference in the stages of functional ischemia Mean SpO2: Fontaine I – 95.50 %, Fontaine II – 92.90; in stage critical ischemia SpO2: Fontaine III – 65.00 % and Fontaine IV – 49.87 %. In 29 patients with gangrenous foot and fingers SpO2 was immeasurable and progressive decrease in SpO2 of arterial capillaries (p<0.01 between stages). CONCLUSIONS Due to the reliability and simplicity of pulse oximetry it can be a routinely used diagnostic device for patients with early determined stage of lower extremities CAI. KEYWORDS Chronic Arterial Insufficiency, SPO2, Pulse Oximetry, Ischemia


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