Atrioventricular nonuniformity of pericardial constraint

Physiologists and clinicians commonly refer to “pressure” as a measure of the constraining effects of the pericardium; however, “pericardial pressure” is really a local measurement of epicardial radial stress. During diastole, from the bottom of the y descent to the beginning of the a wave, pericardial pressure over the right atrium (PpRA) is approximately equal to that over the right ventricle (PpRV). However, in systole, during the interval between the bottom of the x descent and the peak of the v wave, these two pericardial pressures appear to be completely decoupled in that PpRVdecreases, whereas PpRAremains constant or increases. This decoupling indicates considerable mechanical independence between the RA and RV during systole. That is, RV systolic emptying lowers PpRV, but PpRAcontinues to increase, suggesting that the relation of the pericardium to the RA must allow effective constraint, even though the pericardium over the RV is simultaneously slack. In conclusion, we measured the pericardial pressure responsible for the previously reported nonuniformity of pericardial strain. PpRAand PpRVare closely coupled during diastole, but during systole they become decoupled. Systolic nonuniformity of pericardial constraint may augment the atrioventricular valve-opening pressure gradient in early diastole and, so, affect ventricular filling.

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Traumatic tricuspid insufficiency in a kitten

Journal of the American Animal Hospital Association ◽

10.5326/15473317-35-1-21 ◽

1999 ◽

Vol 35 (1) ◽

pp. 21-24 ◽

Cited By ~ 2

Author(s):

JM Closa ◽

A Font

Keyword(s):

Pleural Effusion ◽

Right Ventricle ◽

Papillary Muscle ◽

Atrioventricular Valve ◽

Chordae Tendineae ◽

Color Flow ◽

Tricuspid Insufficiency ◽

Muscle Insertion ◽

Valve Insufficiency ◽

The Right

A four-month-old, male, common European kitten developed pleural effusion and ascites after falling from a fourth-floor flat. Radiographic, bidimensional echocardiography and color-flow Doppler findings were compatible with right-sided atrioventricular valve insufficiency. Necropsy confirmed the diagnosis that tricuspid insufficiency resulted from the rupture of the chordae tendineae of the nonseptal cusp of the valve at the level of the cranial papillary muscle insertion in the right ventricle.

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Assessment of right ventricular diastolic suction in dogs with the use of wave intensity analysis

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00853.2005 ◽

2006 ◽

Vol 291 (6) ◽

pp. H3114-H3121 ◽

Cited By ~ 14

Author(s):

Yichun Sun ◽

Israel Belenkie ◽

Jiun-Jr Wang ◽

John V. Tyberg

Keyword(s):

Right Atrial ◽

Thin Wall ◽

Intensity Analysis ◽

Systolic Volume ◽

End Systolic Volume ◽

Pericardial Pressure ◽

Valve Opening ◽

Pulmonary Arterial ◽

Nonspherical Shape ◽

The Right

Diastolic suction (DS) can be defined as that property of the ventricle by means of which it tends to refill itself during early diastole, independent of any force from the atrium. Although thought to be significant in the left ventricle (LV), DS in the right ventricle (RV) has received little attention, probably because of RV geometry. Our recent LV studies have shown that DS is related to both decreased elastance (i.e., τ, the relaxation time constant) and end-systolic volume (VLVES), thus reconciling the two mechanisms that have been used to explain the concept of DS. We hypothesized that RV DS would similarly depend on τ and VRVES. In six anesthetized open-chest dogs, aortic, RV, right atrial (RA), pulmonary arterial (PA), and RV pericardial pressure, tricuspid velocity, and PA flow were measured. VRVES was calculated by measuring distances between eight ultrasonic crystals. An empirical index of relaxation, τ′, and VRVES were manipulated by volume loading/caval constriction and isoproterenol/esmolol. We calculated the total energy (IW−) of the backward expansion wave generated during RV relaxation and that component causing DS [IW−(DS)]; i.e., the energy remaining after tricuspid valve opening. IW− [IW−(DS) also] was found to be inversely related to τ′ and to VRVES {i.e., IW− = −8.85· e(−0.0423τ′)· e[−0.0665(%VRVES)]}. Thus, as for the LV, the energy of the backward-going wave generated by the RV during relaxation depends on both the rate at which elastance decreases and the completeness of ejection. Despite the thin wall and nonspherical shape of the RV, DS appears to be an important mechanism.

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Quantification of effect of pericardium on LV diastolic PV relation in dogs

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1987.252.5.h963 ◽

1987 ◽

Vol 252 (5) ◽

pp. H963-H968 ◽

Cited By ~ 3

Author(s):

M. Junemann ◽

O. A. Smiseth ◽

H. Refsum ◽

R. Sievers ◽

M. J. Lipton ◽

...

Keyword(s):

Pericardial Effusion ◽

Right Ventricle ◽

Diastolic Pressure ◽

Left Ventricular ◽

Volume Loading ◽

Upward Shift ◽

Volume Curve ◽

Pericardial Pressure ◽

Volume Relation ◽

The Right

The aim of the present study was to quantify the effect of the pericardium on the left ventricular (LV) diastolic pressure-volume relation. The experiments were done in 10 anesthetized closed-chest dogs. Pericardial and cardiac volumes were determined by computed tomography. Pericardial effusion (n = 5) and volume loading (6% dextran iv; n = 5) were used to increase pericardial volume. Volumes were normalized as multiples of the LV volume measured when LV transmural pressure was 6 mmHg (VLV6). Using the data from the pericardial effusion experiments, we calculated the best-fit exponential equations for the pericardial pressure-volume relations. From these equations we calculated that the changes in pericardial volume necessary to shift the LV diastolic pressure-volume curve upward by 2, 5, 10, and 20 mmHg were 0.6 +/- 0.1, 1.1 +/- 0.2, 1.6 +/- 0.2, and 2.2 +/- 0.3 times VLV6, respectively. Using the data from the volume loading experiments, we also calculated the degree of upward shift of the LV pressure-volume relation caused by volume loading, which increased LV mean diastolic pressure by 12 mmHg. (The upward shift is that increment in pericardial pressure caused by the total increase in volume of the extra-LV contents of the pericardium, i.e., the atria, the right ventricle, and any pericardial effusion.) This volume loading increased the total volume of the right ventricle and the atria by 1.0 +/- 0.1 VLV6, which, in itself, increased pericardial pressure by 3.6 +/- 0.8 mmHg. We conclude that in situations in which heart or pericardial volume increases acutely, the pericardium shifts the diastolic pressure-volume relation of the LV upward by a significant amount.

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Regional variation in pericardial contact pressure in the canine ventricle

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.255.6.h1370 ◽

1988 ◽

Vol 255 (6) ◽

pp. H1370-H1377 ◽

Cited By ~ 5

Author(s):

B. D. Hoit ◽

W. Y. Lew ◽

M. LeWinter

Keyword(s):

Left Ventricle ◽

Right Ventricle ◽

Contact Pressure ◽

Regional Variation ◽

Left Atrial ◽

Regional Distribution ◽

Lateral Wall ◽

Cardiac Volume ◽

Pericardial Pressure ◽

The Right

We studied eight open-chest dogs to determine whether there is regional variation in pericardial contact pressure (PCP). Flat, air-filled balloons were used to measure PCP simultaneously over the lateral walls of the right and left ventricles while cardiac volume was varied by dextran infusion. End-diastolic and mean PCP were significantly higher over the left than right ventricle at high (20.3 +/- 1.0 mmHg) and middle levels (13.7 +/- 0.9 mmHg) of left atrial pressure. At high left atrial pressures, the end-diastolic PCP over the lateral left ventricle was 9.1 +/- 2.4 mmHg compared with 4.3 +/- 2.3 mmHg over the lateral right ventricle (P less than 0.05). At middle levels of left atrial pressures, end-diastolic PCP was 6.2 +/- 3.5 mmHg over the left ventricle and 1.5 +/- 2.4 mmHg over the right ventricle (P less than 0.05). These variations in PCP persisted after severing the pericardial diaphragmatic attachments and after turning the dogs such that one or the other balloon was dependent. Regional distribution of PCP was studied by positioning a single balloon sequentially at multiple ventricular sites. PCP was consistently higher over the lateral wall of the left ventricle than either the anterior or posterior walls of the right or left ventricle. After aortic occlusion, end-diastolic PCP increased more over the left than right ventricle. In contrast, with pulmonary artery occlusion, end-diastolic PCP increased more over the right than left ventricle. Pericardial pressure varies regionally, and a single pericardial pressure may be an oversimplification when used to describe pericardial restraint on the cardiac volume.

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Morphological and morphometric analysis from the heart of Caracara plancus (Carcará)

Journal of Morphological Sciences ◽

10.4322/jms.064413 ◽

2014 ◽

Vol 31 (04) ◽

pp. 225-227

Author(s):

R. Miguel ◽

R. Reinaldo ◽

K. Fraga ◽

A. Galvão ◽

J. Silva ◽

...

Keyword(s):

Left Ventricle ◽

Right Ventricle ◽

Muscle Tissue ◽

Interventricular Septum ◽

Side Wall ◽

Lateral Wall ◽

Longitudinal Axis ◽

Papillary Muscles ◽

Atrioventricular Valve ◽

The Right

Abstract Introduction: Caracara plancus, popularly known as Carcará, is a bird with broad geographic distribution, occurring from the southern United States to Argentina. Owing to importance of the heart during the flight and the lack of studies of this body in caracaras, this research aimed to conduct the description of the morphology and internal and external morphology heart Caracara plancus. Materials and Methods: Using a magnifying glass (TECNIVAL, SQF-F), precision scale and steel caliper, the heart three caracaras were described morphologically, weighed and measured. Results: The weight of hearts averaged 7,246g ± 0,518g. The mean side-to-side axis was 2,196cm ± 0,085cm and 3,366cm ± 0,036cm the longitudinal axis. In the side wall of the right ventricle was obtained the value of 0,185cm ± 0,035cm in the lateral wall of the left ventricle 0,59cm ± 0,014cm and interventricular septum 0,014cm ± 0.52cm. The heart of Carcará has no anterior interventricular groove; however there is the presence of the posterior interventricular sulcus. Internally, the left ventricle was observed, the presence of atrioventricular valves formed by connective tissue 18 tendinous cords, papillary muscles and a bridge crests. In the right ventricle, the atrioventricular valve was formed by muscle tissue and did not submit chordae, papillary muscles, crests or bridge. Conclusion: The heart of Carcará features in its morphology similar to the hearts of other birds and can be checked one right atrioventricular valve constituted by muscle tissue.

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