Right atrial and right ventricular transmural pressures in dogs and humans. Effects of the pericardium.

Hamilton, Douglas R.; Dani, R; Semlacher, Roy A.; Smith, Eldon R.; Kieser, Teresa M.; Tyberg, John V.

doi:10.1161/01.cir.90.5.2492

Cited by 53 publications

(35 citation statements)

References 39 publications

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“…The animals were instrumented through a midline sternotomy (14,16). The pericardium was incised from base to apex, along the interventricular sulcus.…”

Section: Methodsmentioning

confidence: 99%

“…Aortic pressure was measured with an 8-F fluid-filled catheter (Cordis, Miami, FL) introduced through a femoral artery. Pericardial pressure was measured with a flat liquid-containing balloon loosely sutured to the surface of the mid-RV free wall (16,39). PA flow was measured with an ultrasonic flowmeter (Transonic Systems, Ithaca, NY) implanted around the main PA. A pneumatic cuff/constrictor (In Vivo Metrics, Healdsburg, CA) was implanted around the inferior vena cava (IVC) above the diaphragm.…”

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confidence: 99%

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

Sun¹,

Belenkie²,

Wang³

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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-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., , the relaxation time constant) and end-systolic volume (V LVES), thus reconciling the two mechanisms that have been used to explain the concept of DS. We hypothesized that RV DS would similarly depend on and V RVES. 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, Ј, and VRVES were manipulated by volume loading/caval constriction and isoproterenol/esmolol. We calculated the total energy (IWϪ) of the backward expansion wave generated during RV relaxation and that component causing DS [IWϪ(DS)]; i.e., the energy remaining after tricuspid valve opening. IWϪ [IWϪ(DS) also] was found to be inversely related to Ј and to VRVES {i.e., IWϪ ϭ Ϫ8.85 ⅐ e (Ϫ0.0423Ј) ⅐ e [Ϫ0.0665(%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. diastole; hemodynamics; tricuspid valve; velocity; pressure THE UNIQUE CAPABILITIES of wave intensity analysis (WIA) could provide information regarding the dynamics and mechanisms of early right ventricular (RV) filling. Conceptually, diastolic suction (DS) is that property of the ventricle by which it tends to refill itself during early diastole, independent of any force from the atrium. Two apparently different types of mechanistic explanations have emerged. One is decreasing elastance; the other is the degree to which the ventricle empties (i.e., endsystolic volume) (11,12,19,22,38,42). Sabbah and colleagues (31, 32) indicated that RV early diastolic pressure is negative in both humans and dogs (perhaps reflecting RV DS) and that the RV can create a sucking effect during early diastole that may contribute to the filling process. Recently, our group clarified the mechanisms of left ventricular (LV) DS using WIA (41).The purpose of this study was to measure the energy associated with RV relaxation (I WϪ , see below) and to test the hypothesis that I WϪ depends on both the rate at which elastance decreases (Ј, an index of the exponential time constant of RV relaxation) and the completeness of RV emptying [RV end-systolic volume (V RVES )]. In particular, the energy associated with RV DS was identified as that component of I WϪ that remains after the opening of the tricuspid valve [I WϪ(DS) ]. METHODSExperimental ...

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“…The animals were instrumented through a midline sternotomy (14,16). The pericardium was incised from base to apex, along the interventricular sulcus.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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

Sun¹,

Belenkie²,

Wang³

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

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“…28 RV enddiastolic pressure and pericardial pressure are usually very similar. 29 Increases in pericardial pressure with pericardial stretch are associated with comparable increases in RV end-diastolic pressure. 30 -32 In these situations, the intracavitary LVEDP may markedly overestimate the effective filling pressure of the LV, which is determined by subtracting the external constraint (by the RV and pericardium) from the LVEDP.…”

Section: Bleasdale Et Al LV Pacing Reduces Ventricular Interactionmentioning

confidence: 98%

Left Ventricular Pacing Minimizes Diastolic Ventricular Interaction, Allowing Improved Preload-Dependent Systolic Performance

et al. 2004

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Background-Left ventricular (LV) pacing improves hemodynamics in patients with heart failure. We hypothesized that at least part of this benefit occurs by minimization of external constraint to LV filling from ventricular interaction. Methods and Results-We present median values (interquartile ranges) for 13 heart failure patients with LV pacing systems implanted for New York Heart Association class III/IV limitation. We used the conductance catheter method to measure LV pressure and volume simultaneously. External constraint was measured from the end-diastolic pressure-volume relation recorded during inferior vena caval occlusion, during LV pacing, and while pacing was suspended. External constraint to LV filling was reduced by 3.0 (4.6 to 0.6) mm Hg from 4.8 (0.6 to 7.5) mm Hg (PϽ0.01) in response to LV pacing; effective filling pressure (LV end-diastolic pressure minus external constraint) increased by 4.0 (2.2 to 5.8) mm Hg from 17.7 (13.3 to 22.6; PϽ0.01). LV end-diastolic volume increased by 10 (3 to 11) mL from 238 (169 to 295) mL (Pϭ0.01), whereas LV end-systolic volume did not change significantly (Ϫ1 [Ϫ2 to 3] mL from 180 [124 to 236] mL, Pϭ0.97), which resulted in an increase in stroke volume of 11 (5 to 13) mL from 49 (38 to 59) mL (PϽ0.01). LV stroke work increased by 720 (550 to 1180) mL ⅐ mm Hg from 3400 (2110 to 4480) mL ⅐ mm Hg (Pϭ0.01), and maximum dP/dt increased by 120 (2 to 161) mm Hg/s from 635 (521 to 767) mm Hg/s (Pϭ0.03). Conclusions-This study suggests a potentially important mechanism by which LV pacing may produce hemodynamic benefit. LV pacing minimizes external constraint to LV filling, resulting in an increase in effective filling pressure; the consequent increase in LV end-diastolic volume increases stroke volume via the Starling mechanism. (Circulation.

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“…As illustrated by our several previous experimental studies of ventricular interaction (1,9,11,14,23,24), minor-axis dimensions can be used to analyze the phenomena of ventricular interaction in ways that are both useful and consistent.…”

Section: Animal Preparationmentioning

confidence: 99%

A 2D FE model of the heart demonstrates the role of the pericardium in ventricular deformation

Kroeker¹,

Adeeb²,

Tyberg³

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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Finite element (FE) analysis has shown that the septum is subject to axial compression and bending when so deformed. This study examines the effects of acute PAC on the left ventricular (LV) free wall and the role the pericardium may play in these effects. In eight open-chest anesthetized dogs, LV, RV, aortic, and pericardial pressures were recorded under control conditions and with PAC. Model dimensions were derived from two-dimensional echocardiography minor-axis images of the heart. At control (pericardium closed), FE analysis showed that the septum was concave to the LV; stresses in the LV, RV, and septum were low; and the pericardium was subject to circumferential tension. With PAC, RV end-diastolic pressure exceeded LV pressure and the septum inverted. Compressive stresses developed circumferentially in the septum out to the RV insertion points, forming an arch-like pattern. Sharp bending occurred near the insertion points, accompanied by flattening of the LV free wall. With the pericardium open, the deformations and stresses were different. The RV became much larger, especially with PAC. With PAC, the arch-like circumferential stresses still developed in the septum, but their magnitudes were reduced, compared with the pericardium-closed case. There was no free wall inversion and flattening was less. From these FE results, the pericardium has a significant influence on the structural behavior of the septum and the LV and RV free walls. Furthermore, the deformation of the heart is dependent on whether the pericardium is open or closed. ventricular function, right ventricular overload; finite element analysis WE HAVE PREVIOUSLY SHOWN that direct interaction between the left ventricle (LV) and right ventricle (RV) is mediated by the pericardium, as shown by a pericardium-mediated compensation for sudden changes in atrial volume (7). When the pericardium was opened or pericardial pressure was very low, ventricular interaction and volume compensation were lost. Lee and Boughner (15) demonstrated that the pericardium has an almost bilinear stress-strain relationship. At low strains, the pericardium is extremely distensible, but when strains are Ͼ10%, the pericardium is stiff. Thus, over a range of lower heart volumes, the pericardium will expand easily with the heart as it fills, but at some point, it will stiffen and become an ever tighter ring around the minor axis of the heart, resisting further expansion. At this point, the cross-sectional area of the heart would become virtually fixed, and any increase in the area (and thus volume) of one ventricle would have to be accompanied by a concomitant decrease in the other-a relation that we defined as direct ventricular interaction (7). Given this role, the pericardium may be important in the structural responses of the LV and RV free walls and septum when subjected to abnormal pressure loading, particularly at end diastole, when the pericardium is taut.Using finite element (FE) analysis, our group studied the behavior of the interventricular septum during diasto...

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Right atrial and right ventricular transmural pressures in dogs and humans. Effects of the pericardium.

Cited by 53 publications

References 39 publications

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

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

Left Ventricular Pacing Minimizes Diastolic Ventricular Interaction, Allowing Improved Preload-Dependent Systolic Performance

A 2D FE model of the heart demonstrates the role of the pericardium in ventricular deformation

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