Ventricular Volume of Nonbeating Excised Dog Hearts in the State of Elastic Equilibrium

Brecher, Gerhard A.; Kolder, H.; Horres, Alan D.

doi:10.1161/01.res.19.6.1080

Cited by 22 publications

(11 citation statements)

References 17 publications

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“…Previous data which suggested that such a phenomenon could exist were probably a function of the artificial experimental preparations employed. The values for V o determined in the present study compare favorably to those directly measured by Brecher et al 42 It is likely that the diastolic mechanical properties of the left ventricle are changed during global cardiac dilation such as occurs in valvular heart disease. 43 Alterations in the diastolic properties may play a significant role in the deterioration of myocardial function that accompanies cardiac dilation in these diseases.…”

supporting

confidence: 85%

Viscoelastic properties of the diastolic left ventricle in the conscious dog.

Rankin¹,

Arentzen²,

McHale³

et al. 1977

Circulation Research

204

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SUMMARY The mechanical properties of the normal left ventricular wall during diastole were studied in 15 chronically instrumented, conscious dogs. Left ventricular minor and major axis diameters and equatorial wall thickness were measured with implanted pulse-transit ultrasonic dimension transducers. Left ventricular and pleural pressures were measured with high fidelity micromanometers. Circumferential mural stress was calculated by using an ellipsoidal shell theory; circumferential strain was calculated by using a natural strain definition. The static elastic properties of the myocardium were estimated by fitting the stress-strain values at the points of diastasis during a vena caval occlusion to an exponential function. A modified creep test was used to evaluate the series viscous properties of the myocardium. Acute increases in systolic and diastolic loading were produced by inflating implanted aortic occluders for 15 minutes in five dogs. In these dogs, the static stress-strain curves were not altered significantly after this period of pressure loading, indicating tbat short-term series viscous properties are negligible. Parallel viscous properties were evaluated in 10 dogs by means of the variable rate stretch test of dynamic diastolic filling. A viscoelastic model incorporating a parallel viscous element fit the dynamic stress-strain data better and predicted the static elastic properties more accurately than a simple exponential model. Thus, the mechanical characteristics of the diastolic left ventricle can be represented most precisely by a viscoelastic model that includes a parallel viscous element.AN EXPONENTIAL relationship between ventricular pressure and volume during diastole was first demonstrated by Frank.1 Influenced by Blix, 2 Frank concluded that this observation represented a fundamental relationship between diastolic force and length within the ventricular wall. During the past two decades there has been a renewed interest in describing the mechanical properties of diastolic myocardium, and numerous investigators have confirmed Frank's observations in a variety of experimental preparations. "5 On the basis of these studies it generally has been accepted that, in both the isolated and the intact heart, an exponential relationship exists between left ventricular pressure and volume during diastole. 6 However, several authors recently have suggested that fitting pressure-volume or pressure-dimension data from a single diastolic filling period with a simple exponential function may be an oversimplification. "12 Indeed, previous experiments that demonstrated exponential pressure-dimension curves in the intact heart utilized static measurements during induced volume changes.13 So far as we are aware, there are no directly measured data in the literature which indicate that ventricular pressure and di- Received July 9,1976; accepted for publication December 10,1976. mensions are exponentially related during the dynamic filling of a single diastole. The diastolic mechanical properties of isolate...

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supporting

confidence: 85%

Viscoelastic properties of the diastolic left ventricle in the conscious dog.

Rankin¹,

Arentzen²,

McHale³

et al. 1977

Circulation Research

204

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“…32), this implies that the RV will tend to refill itself until transmural pressure is zero and that the smaller the end-systolic volume, the greater the DS. The concept of an equilibrium volume (8) or elastic recoil (4, 7) implies that restoring forces in the ventricle promote filling when RV volume is less than the equilibrium volume. Thus factors that augment RV emptying will tend to increase the gradient for filling during the subsequent diastole (40).…”

Section: Discussionmentioning

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

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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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“…However, Brecher et al (10) reported no change in the volumepressure curves 3 hours after death. The apparent discrepancy may be attributed to the lower temperature of their Ringer solution (10°C).…”

Section: Discutiionmentioning

confidence: 97%

“…Parenthetically, an investigator employing univentricular injection may obtain values more closely related to the in vivo state if he has allowed the establishment of rigor mortis. The above considerations serve to limit the usefulness of many observations in which the ventricular chambers were measured after death (3,(9)(10)(11).…”

Section: Discutiionmentioning

confidence: 99%

Volumes and Compliances Measured Simultaneously in the Right and Left Ventricles of the Dog

Laks

Garner

Swan

1967

Circulation Research

156

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In 10 normal dogs, the right and left ventricular volumes and compliances were determined in the fresh post-mortem heart. With the use of a SigmaMotor pump, Ringer's solution at 23°C was simultaneously infused into both ventricles within an hour after death. When the ventricles were full but open to atmospheric pressure, the mean volumes were 35.8 ml/m 2 for the right and 23.1 ml/m 2 for the left ventricle; when the transmural pressure was increased by 10 mm Hg, the mean volumes were 56.9 ml/m-for the right and 41.9 ml/ m-for the left ventricle; at 20 mm Hg, the values were 60.8 and 48.5 ml/m-, respectively. The initial volumes and the increases in volume produced by increase in transmural pressure were affected by the position of the ventricular septum and by the presence of rigor mortis. With infusions into only one ventricle, right and left ventricular volumes were 20 to 74% greater at 10 mm Hg than the values when both ventricles were filled simultaneously. Compliance began to decrease 40 to 60 min after death; at 130 min after death (23°C), the change in volume when the transmural pressure was increased to 10 mm Hg was only about 1/5 of that immediately after death.ADDITIONAL KEY WORDS rigor mortis ventricular septum pressure-volume curves unilateral vs. bilateral filling• The purpose of these experiments was to study, in the fresh post-mortem heart, the volume-pressure relationships of the right and left ventricles of the dog. Such relationships previously reported are difficult to interpret, and are of uncertain relevance to conditions in vivo, because the effects of rigor mortis were not always considered and because in previous studies fluid was infused into only one ventricle at a time (1-3). In the present study we have found that volume-pressure relationships are highly dependent upon the state of filling of the contra-lateral chamber. Hence, the values of volume and compliance reported here, using the technique of simul- This study was supported by Public Health Service Research Crant HE 10382 from the National Heart Institute and the Ives Laboratories.Accepted for publication March 28, 1967. taneous biventricular filling, are probably physiologically more meaningful. MethodsTen mongrel dogs weighing between 12 and 23 kg were intravenously anesthetized with sodium pentobarbital, 27 mg/kg. A midstemal incision was rapidly made and the vessels, esophagus, and trachea were transected; the beating heart was then immersed in Ringer's solution at 23°C. The pericardium was incised and slipped to its insertion on the great vessels. The pericardium and other tissues were cut away leaving the atria and ventricles intact. With the use of Ringer's solution, blood was flushed from both ventricles. Polyethylene catheters, PE 240 (o.d. = 082 inches; i.d. = .062 inches), were inserted into the left and right ventricles via the atrioventricular valves. Heavy cotton suture, securely tied at the atrio-ventricular groove, closed off the ventricular inflow tracts. Two other polyethylene catheters, inserted in...

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Ventricular Volume of Nonbeating Excised Dog Hearts in the State of Elastic Equilibrium

Cited by 22 publications

References 17 publications

Viscoelastic properties of the diastolic left ventricle in the conscious dog.

Viscoelastic properties of the diastolic left ventricle in the conscious dog.

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

Volumes and Compliances Measured Simultaneously in the Right and Left Ventricles of the Dog

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