Left ventricular wave speed

2001 ◽  
Vol 91 (6) ◽  
pp. 2531-2536 ◽  
Author(s):  
Jiun-Jr Wang ◽  
Kim H. Parker ◽  
John V. Tyberg
Keyword(s):  
Wave Speed ◽  
Pulse Generator ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Pressure Transducers ◽  
Pressure Area ◽  
Axis Length

Left ventricular (LV) wave speed (LVWS) was studied experimentally and confirmed in theory. Combining the definition of elastance (E) with the equations for the conservation of mass and momentum shows that LVWS is proportional to the square root of E LA, where L is long-axis length and A is the cross-sectional area, and the density of the blood. (We defined E LA = γ, where γ is compressibility.) We studied nine open chest, anesthetized dogs, three of which were studied during caval constriction when LV end-diastolic pressure was ≤0 mmHg. The hearts were paced at ∼90 beats/min, and LV cross-sectional area was measured by using two pairs of ultrasonic crystals; E was calculated from the LV pressure-area loop. A pulse generator was connected to the LV apex, and LVWS was measured by using two pressure transducers: one near the apex and the other near the base. Their distance was measured roentgenographically and compared with the diameter of a reference ball. LVWS ranged from ∼1 m/s during diastole to ∼10 m/s during systole. The slope of the log c(where c is wave speed) vs. log γ was 0.546, which is in agreement with theory (0.5). When γ ≤ 0, LVWS was ∼1.5 m/s.

Relation between Coronary Artery Cross Sectional Area and Left Ventricular Wall Mass

1990 ◽  
Vol 20 (4) ◽  
pp. 748
Author(s):  
Doo Hong Choi ◽  
Hak Sun Kim ◽  
Sun Ho Chang ◽  
Joo Young Cho ◽  
Sung Gu Kim ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Left Ventricular Wall ◽  
Ventricular Wall ◽  
Sectional Area ◽  
Cross Sectional ◽  
Wall Mass

Left ventricular force-length relations of isovolumic and ejecting contractions

1976 ◽  
Vol 231 (2) ◽  
pp. 337-343 ◽  
Author(s):  
KT Weber ◽  
JS Janicki ◽  
LL Hefner
Keyword(s):  
Left Ventricle ◽  
Linear Function ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Sectional Area ◽  
Active Force ◽  
Cross Sectional ◽  
Contractile State ◽  
State Dependent ◽  
Ejection Pressure

To determine the interrelationships between ejecting and isovolumic force-length relations and the extent to which the left ventricle will shorten, data obtained in 27 isolated, servo-regulated hearts were examined. For each heart a series of contractions, variably loaded (delta L) were derived for a thickwalled sphere and normalized by the cross-sectional area of muscle and length at zero end-diastolic pressure. It was found that within the physiological range examined total and active force were essentially a linear function of initial L with respective increments or reductions in slope produced by positive or negative shifts in contractile state. The force-L relations obtained isovolumically and at end ejection were virtually identical. For a given ejection pressure, end-systolic L was constant, despite variations in filling and therefore independent of initial L and deltaL; moreover, the L to which the ventricle shortened was determined by the course of the systolic force L-relation. Thus, irrespective of loading, delta L occurs within the confines of the contractile state-dependent isovolumic force-L relation and where the latter is equivalent to the end-systolic force-length relation.

The Use of a Laser Micrometer System to Determine the Cross-Sectional Shape and Area of Ligaments: A Comparative Study With Two Existing Methods

1990 ◽  
Vol 112 (4) ◽  
pp. 426-431 ◽  
Author(s):  
Savio L.-Y. Woo ◽  
Michael I. Danto ◽  
Karen J. Ohland ◽  
Thay Q. Lee ◽  
Peter O. Newton
Keyword(s):  
Constant Pressure ◽  
Cruciate Ligament ◽  
Applied Pressure ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Proximal Site ◽  
Pressure Area ◽  
The Cross ◽  
Sectional Shape

Determination of the tensile stresses in ligaments and tendons during uniaxial loading depends on accurate measurement of the cross-sectional area. In this study, a laser micrometer system was employed to evaluate the cross-sectional shape and area of the medial collateral ligament (MCL) at three locations and anterior cruciate ligament (ACL). In a New Zealand White (NZW) rabbit, morphologic sections of the ligaments were made to verify the cross-sectional shape reconstructed by the laser micrometer system. The areas obtained by the laser micrometer system from ten additional NZW rabbits were compared with those obtained by two other methods commonly used to measure the cross-sectional area of ligaments and tendons: one method uses digital calipers and the other a constant pressure (0.12 MPa) area micrometer. For the MCL, the digital calipers yielded results very similar to those of the laser micrometer, but the constant pressure area micrometer yielded values 20 percent lower. The area measured at the proximal site of the MCL was 13 percent greater than the area measured at the joint line and distal line. For the ACL, the values obtained by the digital calipers and constant pressure area micrometer were 16 and 20 percent lower, respectively. Because of the irregular shape exhibited by the rabbit ACL, the digital calipers could not accurately measure the crosssectional area. The constant pressure area micrometer yielded lower values for the cross-sectional area of both the MCL and ACL, presumably due to the applied pressure which caused changes in both the cross-sectional shape and area.

Left atrial cross-sectional area is a novel measure of atrial shape associated with cardioembolic strokes

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 ◽  
...  
Keyword(s):  
Ischaemic Stroke ◽  
Flow Velocity ◽  
Left Atrial ◽  
Velocity Profiles ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Left Ventricular Ejection ◽  
Sectional Area ◽  
Cross Sectional

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.

P5457Assessment of carotid cross sectional area in hypertensive patients: phenotyping and prognostic validation in the campania salute network

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
C Mancusi ◽  
R Izzo ◽  
M A Losi ◽  
E Barbato ◽  
V Trimarco ◽  
...  
Keyword(s):  
Left Ventricular ◽  
Cross Sectional Area ◽  
Older Age ◽  
Prognostic Impact ◽  
Sectional Area ◽  
Cross Sectional ◽  
Hypertensive Patients ◽  
Cox Regression Analysis ◽  
Increased Risk ◽  
Male Sex

Abstract Background Increased intima media thickness (IMT) of common carotid artery (CA) is considered the hallmark of vascular hypertension-mediated target organ damage, even though vessel remodeling due to mechanical stress can be accompanied also by changes in diameter. Purpose We developed a method computing both diameter and IMT of CA, and assessed correlates and prognostic impact of carotid cross sectional area (CCSA) in a large registry of treated hypertensive patients. Methods We selected 7049 hypertensive patients of the Campania Salute Network registry free of overt cardiovascular (CV) disease and with available CA ultrasound (54±11 yrs; 57% male). CCSA was computed as: π × [((CA diameter + 2 × (mean IMT)) / 2)]2 − π × [((CA diameter) / 2)]2. Results CCSA was considered high if >90th percentile of the sex-specific distribution (>48 mm2 in men and >41 mm2 in women). Higher CCSA correlated with older age, male sex, higher pulse pressure (PP), higher total and LDL cholesterol and presence of diabetes (p<0.01 for all). During a median follow-up of 45 months (IQR 19–92), 324 incident composite major and minor CV events occurred. In Cox regression analysis high CCSA was associated with more than 100% increased risk of incident CV events (p<0.0001, figure), independently of the effect of older age, male sex, PP>60mmHg, presence of left ventricular hypertrophy (LVH), carotid plaque (CP), and less anti-RAS therapy (p<0.05 for all). Conclusions In treated hypertensive patients, increased CCSA is associated with worse metabolic and lipid profile and predict incident CV events, independently of high PP, presence of LVH and CP.

Advancement of the mandible improves velopharyngeal airway patency

1995 ◽  
Vol 79 (6) ◽  
pp. 2132-2138 ◽  
Author(s):  
S. Isono ◽  
A. Tanaka ◽  
Y. Sho ◽  
A. Konno ◽  
T. Nishino
Keyword(s):  
Static Pressure ◽  
Video Recording ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Airway Patency ◽  
Pharyngeal Airway ◽  
Obstructive Sleep ◽  
Pressure Area ◽  
Nasal Pressure

The velopharynx is the most common site of obstruction in patients with obstructive sleep apnea (OSA). Advancement of the mandible effectively reverses the pharyngeal obstruction. Accordingly, we hypothesized that mandibular advancement increases cross-sectional area of several segments of the upper airway, including the velopharynx and the oropharynx. We examined the pressure-area properties of the pharyngeal airway in 13 patients with OSA. Under general anesthesia and total muscle paralysis, the pharynx was visualized with an endoscope connected to a video-recording system. During an experimentally induced apnea, we manipulated the nasal pressure from 20 cmH2O to the point of total closure at the velopharynx. The procedure was repeated after maximal forward displacement of the mandible. Measurements of the cross-sectional area at different levels of nasal pressure allowed construction of a static pressure-area relationship of the “passive pharynx,” where active neuromuscular factors are suppressed. In 12 of 13 patients with OSA, advancement of the mandible stabilized the airway by reducing the closing pressure and increasing the area at any airway pressure. Thus the maneuver shifted the static pressure-area curve of the velopharynx and the oropharynx upward in these patients. We conclude that anterior movement of the mandible widens the retropalatal airway as well as that at the base of the tongue in the passive pharynx of OSA patients.

Two-Dimensional and M-Mode Echocardiographic Predictors of Disease Severity in Dogs With Congenital Subaortic Stenosis

2002 ◽  
Vol 38 (3) ◽  
pp. 209-215 ◽  
Author(s):  
Mark A. Oyama ◽  
William P. Thomas
Keyword(s):  
Disease Severity ◽  
Ventricular Outflow Tract ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Subaortic Stenosis ◽  
Two Dimensional ◽  
Sectional Area ◽  
Cross Sectional ◽  
Left Ventricular Outflow ◽  
The Cross

Echocardiographic studies from 50 dogs with congenital subaortic stenosis were examined. The degree of concentric, left-ventricular hypertrophy as assessed by M-mode measurement demonstrated a positive relationship (P &lt;0.05) to disease severity. However, the clinical utility of these measures is hindered by a large amount of individual variation (r2=0.243 to 0.473). Two-dimensional ultrasound was used to compare the cross-sectional area of the left-ventricular outflow tract to the cross-sectional area of the aortic root. The ratio of these two areas demonstrated a strong inverse relationship (P=0.001; r2=0.778) with disease severity. This ratio provides a method of estimating severity of disease by two-dimensional echocardiography.

Left Ventricular Function: Correlation With Deformation of the Myocardium

1978 ◽  
Vol 100 (2) ◽  
pp. 99-104 ◽  
Author(s):  
C. A. Phillips ◽  
E. S. Grood ◽  
R. E. Mates ◽  
H. L. Falsetti
Keyword(s):  
Cardiac Cycle ◽  
Volume Overload ◽  
Left Ventricular ◽  
Area Ratio ◽  
Equatorial Region ◽  
Cross Sectional Area ◽  
Tissue Deformation ◽  
Sectional Area ◽  
Cross Sectional ◽  
Congestive Cardiomyopathy

The amount of local tissue deformation at the equatorial region of the left ventricle is quantitated by the ratio of the instantaneous cross-sectional area of a tissue element to the cross-sectional area at end-diastole. The area ratio, AR, was computed for the circumferential and longitudinal, apex to base, direction throughout the cardiac cycle from catheterization and cineangiographic data on 36 patients. The patients were divided into four groups: normal left ventricualr function—15, compensated volume overload—6, decompensated volume overload—9, and congestive cardiomyopathy—6. The peak longitudinal area ratio was elevated in the compensated group (P <0.001) and not statistically significant from normal in the decompensated group. A larger fraction of the cardiac cycle was required to reach the peak longitudinal (p <0.01) and circumferential (p <0.05) area ratio in the compensated group. The volume overload compensatory process apparently involves a change in the relative magnitude and timing of tissue deformation. The hypo-contractile ventricle was characterized by a reduction in the sum of the logitudinal and circumferential area ratios, which for all six patients in the congestive cardiomyopathy group, had a value less than any of the other thirty patients.

Increased carotid cross-sectional area is a marker of organ damage in young hypertensive patients

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M De Marco ◽  
C Mancusi ◽  
G Canciello ◽  
M.G Losi ◽  
B Trimarco ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
Carotid Plaque ◽  
Organ Damage ◽  
Left Ventricular ◽  
Cross Sectional Area ◽  
Prognostic Impact ◽  
Sectional Area ◽  
Cross Sectional ◽  
Hypertensive Patients

Abstract Background Common Carotid artery (CA) cross sectional area (CCSA) is strictly related to vessel remodelling stimulated by mechanical stress due to arterial hypertension. Accordingly, increased CCSA might represent an early marker of vascular target organ damage independently of presence of atherosclerotic plaque. Purpose To assess early correlates and prognostic impact of CCSA in a large population of young treated HTN patients. Methods We selected 970 hypertensive patients, 18 to 40 years old (mean age 34±5 yrs; 30% women) of the Campania Salute Network registry with available CA ultrasound and follow-up data, free of overt cardiovascular (CV) disease. CCSA was computed as: CCSA = π [(CAd/2 + IMT)2 – (CAd/2)2] where CAd = CA diameter and IMT = mean intima media thickness. Participants were compared by CCSA tertiles. Results Compared to the lowest and intermediate tertiles, patients in the highest tertile were more often male, smokers, older, and had higher body mass index (BMI), diastolic blood pressure (BP), higher fasting glucose, triglycerides, LDL cholesterol and uric acid, with lower level of HDL cholesterol. They also exhibited higher left ventricular mass index and IMT and had more often carotid atherosclerotic plaque (all p&lt;0.05). During a median follow-up of 45 months, 22 incident composite CV events occurred. In Cox-Regression analyses, adjusting for the above covariates, presence of carotid plaque and classes of antihypertensive medications, increased CCSA was significantly associated with increased CV risk (HR 1.08/mm2; 95% CI 1.02–1.13; p&lt;0.01). Conclusions In a population of young hypertensive patients, increased CCSA is related to metabolic and atherosclerotic disease and is associated with increased CV risk, also independently of overt carotid plaque. Funding Acknowledgement Type of funding source: None

Sign in / Sign up

Export Citation Format

Share Document