Influence of posture on left ventricular long- and short-axis shortening

2002 ◽  
Vol 283 (4) ◽  
pp. H1302-H1306 ◽  
Author(s):  
Patrik Sundblad ◽  
Bengt Wranne
Keyword(s):  
Supine Position ◽  
Healthy Subjects ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Upright Position ◽  
Lateral Part ◽  
Short Axis ◽  
Spherical Form ◽  
End Diastolic Volume ◽  
Axis Length

End-diastolic volume and left ventricular stroke volume are increased in the supine compared with upright position, but the contribution of long-axis (LAS) and short-axis shortening (SAS) to these changes with change in posture has not been established. We examined long- and short-axis motion and dimensions with echocardiography in 10 healthy subjects in the upright and supine position. Long-axis length at end diastole was almost identical, whereas the diastolic short-axis diameter was increased in the supine position. At end systole, there was a decreased long-axis length and increased short-axis length in the supine vs. upright position. Both LAS and SAS were enhanced in supine vs. upright positions [LAS: 9.3 ± 2.2 vs. 15.1 ± 3.1 mm ( P < 0.001); SAS: 12.7 ± 3.2 vs. 16.3 ± 2.8 mm ( P < 0.001)], presumably via Starling mechanisms. LAS increased more in the lateral part of the mitral annulus than in the septal part [7.7 ± 2.6 vs. 4.0 ± 2.8 mm ( P < 0.006)], which implies that the more spherical form, in the supine position, induces more stretch at the lateral free wall than in the ventricular septum. These findings support the notion that Starling mechanisms affect systolic LAS.

Supine position decreases the ability of the nose to warm and humidify air

2001 ◽  
Vol 91 (6) ◽  
pp. 2459-2465 ◽  
Author(s):  
Paraya Assanasen ◽  
Fuad M. Baroody ◽  
Edward Naureckas ◽  
Julian Solway ◽  
Robert M. Naclerio
Keyword(s):  
Supine Position ◽  
Healthy Subjects ◽  
Air Conditioning ◽  
Upright Position ◽  
Nasal Mask ◽  
Total Water ◽  
Nasal Turbinate ◽  
Dry Air ◽  
Air Volume ◽  
Water Gradient

We tested the hypothesis that decreasing nasal air volume (i.e., increasing nasal turbinate blood volume) improves nasal air conditioning. We performed a randomized, two-way crossover study on the conditioning capacity of the nose in six healthy subjects in the supine and upright position. Cold, dry air (CDA) was delivered to the nose via a nasal mask, and the temperature and humidity of air were measured before it entered and after it exited the nasal cavity. The total water gradient (TWG) across the nose was calculated and represents the nasal conditioning capacity. Nasal volume decreased significantly from baseline without changing the mucosal temperature when subjects were placed in the supine position ( P < 0.01). TWG in supine position was significantly lower than that in upright position ( P < 0.001). In the supine position, nasal mucosal temperature after CDA exposure was significantly lower than that in upright position ( P < 0.01). Our data show that placing subjects in the supine position decreased the ability of the nose to condition CDA compared with the upright position, in contrast to our hypothesis.

Atrioventricular plane displacement is the major contributor to left ventricular pumping in healthy adults, athletes, and patients with dilated cardiomyopathy

2007 ◽  
Vol 292 (3) ◽  
pp. H1452-H1459 ◽  
Author(s):  
Marcus Carlsson ◽  
Martin Ugander ◽  
Henrik Mosén ◽  
Torsten Buhre ◽  
Hakan Arheden
Keyword(s):  
Dilated Cardiomyopathy ◽  
Healthy Subjects ◽  
Radial Function ◽  
Left Ventricular ◽  
Lv Function ◽  
Short Axis ◽  
Resonance Imaging ◽  
Atrioventricular Plane Displacement ◽  
The Mean ◽  
Plane Displacement

Previous studies using echocardiography in healthy subjects have reported conflicting data regarding the percentage of the stroke volume (SV) of the left ventricle (LV) resulting from longitudinal and radial function, respectively. Therefore, the aim was to quantify the percentage of SV explained by longitudinal atrioventricular plane displacement (AVPD) in controls, athletes, and patients with decreased LV function due to dilated cardiomyopathy (DCM). Twelve healthy subjects, 12 elite triathletes, and 12 patients with DCM and ejection fraction below 30% were examined by cine magnetic resonance imaging. AVPD and SV were measured in long- and short-axis images, respectively. The percentage of the SV explained by longitudinal function (SVAVPD%) was calculated as the mean epicardial area of the largest short-axis slices in end diastole multiplied by the AVPD and divided by the SV. SV was higher in athletes [140 ± 4 ml (mean ± SE), P = 0.009] and lower in patients (72 ± 7 ml, P < 0.001) when compared with controls (116 ± 6 ml). AVPD was similar in athletes (17 ± 1 mm, P = 0.45) and lower in patients (7 ± 1 mm, P < 0.001) when compared with controls (16 ± 0 mm). SVAVPD%was similar both in athletes (57 ± 2%, P = 0.51) and in patients (67 ± 4%, P = 0.24) when compared with controls (60 ± 2%). In conclusion, longitudinal AVPD is the primary contributor to LV pumping and accounts for ∼60% of the SV. Although AVPD is less than half in patients with DCM when compared with controls and athletes, the contribution of AVPD to LV function is maintained, which can be explained by the larger short-axis area in DCM.

Failed Downregulation of Circulating MicroRNA-155 in the Early Phase after ST Elevation Myocardial Infarction Is Associated with Adverse Left Ventricular Remodeling

Cardiology ◽  
2017 ◽  
Vol 138 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Sam C. Latet ◽  
Paul L. Van Herck ◽  
Marc J. Claeys ◽  
Amaryllis H. Van Craenenbroeck ◽  
Steven E. Haine ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Healthy Subjects ◽  
Noncoding Rna ◽  
Left Ventricular ◽  
St Elevation Myocardial Infarction ◽  
Circulating Microrna ◽  
Second Phase ◽  
End Diastolic Volume ◽  
Lv Remodeling ◽  
St Elevation

Background: MicroRNA are noncoding RNA that have a significant role in both inflammatory and cardiovascular diseases. Aims: We aimed to assess whether the inflammation-related microRNA-155 is associated with the development of adverse left ventricular (LV) remodeling following ST elevation myocardial infarction (STEMI). Methods: Peripheral blood samples were collected in the inflammatory (day 2), proliferative (day 5), and maturation phases (6 months) after STEMI (n = 20). Granulocytes, monocytes, and lymphocytes were enumerated with flow cytometry. The changes in LV volumes were assessed with 3-D echocardiography on day 1 and after 6 months. Adverse remodeling was defined as a >20% increase in end-diastolic volume. Healthy subjects were recruited as controls. Results: MicroRNA-155 measured on day 5 correlated positively with the relative change in end-diastolic volume (ρ = 0.490, p = 0.028). MicroRNA-155 (day 5) was significantly higher in patients with compared to patients without adverse LV remodeling. The expression level was similar in healthy subjects (n = 8) and in patients with LV remodeling. There was a positive correlation between microRNA-155 and the amount of monocytes (day 5, ρ = 0.463, p = 0.046). Conclusion: Impaired downregulation of microRNA-155 during the second phase of the post- STEMI inflammatory response is a determinant of the development of adverse LV remodeling.

Left Ventricular End-Diastolic Volume in Advanced Ischemic Heart Disease; Comparison between Healthy Subjects and Patients with Mitral Stenosis

Cardiology ◽  
1975 ◽  
Vol 60 (2) ◽  
pp. 86-97
Author(s):  
J. Kasalick&yacute; ◽  
J. Fabi&aacute;n ◽  
J. Ressl ◽  
P. Jebav&yacute; ◽  
V. Stanek
Keyword(s):  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Mitral Stenosis ◽  
Healthy Subjects ◽  
Left Ventricular ◽  
Ischemic Heart ◽  
End Diastolic Volume

An approach for comparative quantification of myocardial blood flow (0-15-H2O-PET), perfusion (Tc-99m-tetrofosmin-SPECT), and metabolism (F 18-FDG-PET)

2001 ◽  
Vol 40 (05) ◽  
pp. 164-171 ◽  
Author(s):  
B. Nowak ◽  
H.-J. Kaiser ◽  
S. Block ◽  
K.-C. Koch ◽  
J. vom Dahl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Fdg Pet ◽  
Model Fitting ◽  
Compartment Model ◽  
Left Ventricular ◽  
Short Axis ◽  
New Approach ◽  
Single Compartment Model ◽  
Tissue Fraction

Summary Aim: In the present study a new approach has been developed for comparative quantification of absolute myocardial blood flow (MBF), myocardial perfusion, and myocardial metabolism in short-axis slices. Methods: 42 patients with severe CAD, referred for myocardial viability diagnostics, were studied consecutively with 0-15-H2O PET (H2O-PET) (twice), Tc-99m-Tetrofosmin 5PECT (TT-SPECT) and F-18-FDG PET (FDG-PET). All dato sets were reconstructed using attenuation correction and reoriented into short axis slices. Each heart was divided into three representative slices (base, rnidventricular, apex) and 18 ROIs were defined on the FDG PET images and transferred to the corresponding H2O-PET and TT-SPECT slices. TT-SPECT and FDG-PET data were normalized to the ROI showing maximum perfusion. MBF was calculated for all left-ventricular ROIs using a single-compartment-model fitting the dynamic H2O-PET studies. Microsphere equivalent MBF (MBF_micr) was calculated by multiplying MBF and tissue-fraction, a parameter which was obtained by fitting the dynamic H2O-PET studies. To reduce influence of viability only well perfused areas (>70% TT-SPECT) were used for comparative quantification. Results: First and second mean global MBF values were 0.85 ml × min-1 × g-1 and 0.84 ml × min-1 × g1, respectively, with a repeatability coefficient of 0.30 ml ÷ min-1 × gl. After sectorization mean MBF_micr was between 0.58 ml × min1 ÷ ml"1 and 0.68 ml × min-1 × ml"1 in well perfused areas. Corresponding TT-SPECT values ranged from 83 % to 91 %, and FDG-PET values from 91 % to 103%. All procedures yielded higher values for the lateral than the septal regions. Conclusion: Comparative quantification of MBF, MBF_micr, TT-SPECT perfusion and FDG-PET metabolism can be done with the introduced method in short axis slices. The obtained values agree well with experimentally validated values of MBF and MBF_micr.

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