Hemodynamic consequences of ventricular interaction as assessed by model analysis

1991 ◽  
Vol 260 (1) ◽  
pp. H146-H157 ◽  
Author(s):  
W. P. Santamore ◽  
D. Burkhoff
Keyword(s):  
Right Ventricular ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Free Wall ◽  
Left Ventricular Free Wall ◽  
Right Ventricular Free Wall ◽  
Ventricular Interaction ◽  
Ventricular Interdependence

Because of close anatomic association, the pressure and volume in one ventricle can directly influence the pressure and volume in the opposite ventricle. To examine the importance of ventricular interdependence in controlling the circulation, we developed a computer model in which ventricular interdependence could be turned on and off. Left ventricular chamber contractility, as judged by maximal elastance (Emax), was enhanced on the order of 10% as a result of ventricular interaction, whereas right ventricular Emax was affected by as much as 60% under physiological conditions. With increases in systemic vascular resistance, ventricular interaction caused a smaller stroke volume (SV) decrease than with no interaction. For canine data (SV = 21.4 ml), doubling systemic vascular resistance decreased SV by 3.7 without ventricular interdependence, 3.5 with diastolic ventricular interdependence, and 3.3 ml with diastolic and systolic ventricular interdependence. In contrast, with increases in pulmonary vascular resistance, ventricular interaction caused a greater decrease in SV than with no interaction present. Decreasing left ventricular free wall elastance or right ventricular free wall elastance decreased SV. Diastolic ventricular interdependence reduced the SV changes, whereas systolic ventricular interdependence accentuated the SV changes with alterations in right and left ventricular free-wall elastance. The results of the present simulation demonstrate the importance of ventricular interdependence in the observed responses of the right ventricle to volume overload, pressure overload, and ischemia.

Differential regional gene expression from cardiac dyssynchrony induced by chronic right ventricular free wall pacing in the mouse

2006 ◽  
Vol 26 (2) ◽  
pp. 109-115 ◽  
Author(s):  
Kenneth C. Bilchick ◽  
Sudip K. Saha ◽  
Ed Mikolajczyk ◽  
Leslie Cope ◽  
Will J. Ferguson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Right Ventricular ◽  
Differential Expression ◽  
Stem Cell Differentiation ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Free Wall ◽  
Right Ventricular Free Wall ◽  
Cardiac Dyssynchrony ◽  
Clinical Prognosis

Routine clinical right ventricular pacing generates left ventricular dyssynchrony manifested by early septal shortening followed by late lateral contraction, which, in turn, reciprocally stretches the septum. Dyssynchrony is disadvantageous to cardiac mechanoenergetics and worsens clinical prognosis, yet little is known about its molecular consequences. Here, we report the influence of cardiac dyssynchrony on regional cardiac gene expression in mice. Mice were implanted with a custom-designed miniature cardiac pacemaker and subjected to 1-wk overdrive right ventricular free wall pacing (720 beats/min, baseline heart rate 520–620 beats/min) to generate dyssynchrony (pacemaker: 3-V lithium battery, rate programmable, 1.5 g, bipolar lead). Electrical capture was confirmed by pulsed-wave Doppler and dyssynchrony by echocardiography. Gene expression from the left ventricular septal and lateral wall myocardium was assessed by microarray (dual-dye method, Agilent) using oligonucleotide probes and dye swap. Identical analysis was applied to four synchronously contracting controls. Of the 22,000 genes surveyed, only 18 genes displayed significant ( P < 0.01) differential expression between septal/lateral walls >1.5 times that in synchronous controls. Gene changes were confirmed by quantitative PCR with excellent correlations. Most of the genes ( n = 16) showed greater septal expression. Of particular interest were seven genes coding proteins involved with stretch responses, matrix remodeling, stem cell differentiation to myocyte lineage, and Purkinje fiber differentiation. One week of iatrogenic cardiac dyssynchrony triggered regional differential expression in relatively few select genes. Such analysis using a murine implantable pacemaker should facilitate molecular studies of cardiac dyssynchrony and help elucidate novel mechanisms by which stress/stretch stimuli due to dyssynchrony impact the normal and failing heart.

Comparison of left ventricular free wall and septal diastolic compliance in the dog

1978 ◽  
Vol 234 (4) ◽  
pp. H392-H398 ◽  
Author(s):  
R. S. Kent ◽  
T. E. Carew ◽  
M. M. LeWinter ◽  
J. W. Covell
Keyword(s):  
Right Ventricular ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Segment Length ◽  
Free Wall ◽  
Left Ventricular Free Wall ◽  
Average Maximum ◽  
Diastolic Compliance ◽  
Regional Compliance

Septal to free wall dimensions are frequently employed for the analysis of diastolic compliance. However, the diastolic properties of these anatomically distinct regions of left ventricle are not well characterized. Regional compliance was studied in eight open-chest anesthetized dogs. Pairs of 2-mm-diameter piezoelectric crystals were implanted in the left ventricular free wall or septum 1.38 +/- 0.06 cm apart at a midwall location 58% +/- 1.9 of the left ventricular endocardial-epicardial or left ventricular endocardial-right ventricular endocardial distance. Left ventricular end-diastolic pressure was increased from an average of 8.1-21.0 mmHg, with a resulting average maximum end-diastolic strain of 11% (end-diastolic (ED) segment length/control ED length). Regional stiffness was assessed at all sites based on the relationship between left ventricular end-diastolic pressure and regional strain. Neither strain nor calculated stiffness coefficients differed significantly among the three sites. Septal transmural pressure (left ventricular end-diastolic pressure--right ventricular end-diastolic pressure) was nearly constant as left ventricular end-diastolic pressure increased during volume infusion and thus did not account for the observed septal strain.

Absent Pulmonary Valve with Tricuspid Atresia or Severe Tricuspid Stenosis: Report of Three Cases and Review of the Literature

2000 ◽  
Vol 3 (4) ◽  
pp. 353-366 ◽  
Author(s):  
Silvio Litovsky ◽  
Michael Choy ◽  
Jeanny Park ◽  
Mark Parrish ◽  
Brenda Waters ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Pulmonary Valve ◽  
Left Ventricular ◽  
Tricuspid Atresia ◽  
Ventricular Free Wall ◽  
Ventricular Septum ◽  
Free Wall ◽  
Absent Pulmonary Valve ◽  
Right Ventricular Free Wall ◽  
The Right

Absence of the pulmonary valve occurs usually in association with tetralogy of Fallot and occasionally with an atrial septal defect or as an isolated lesion. Very rarely it occurs with tricuspid atresia, intact ventricular septum, and dysplasia of the right ventricular free wall and of the ventricular septum. We present the clinical, anatomic, and histologic findings of a new case, and for the first time, the data from two patients with absent pulmonary valve and severe tricuspid stenosis, who exhibited similar histologic findings. We also reviewed the clinical and anatomic data of 24 previously published cases and compared them with the new cases. In all three new cases, the myocardium of the right ventricle was very abnormal. In the two cases with tricuspid stenosis, large segments of myocardium were replaced with sinusoids and fibrous tissue. In the case with tricuspid atresia, the right ventricular free wall contained only fibroelastic tissue. The ventricular septum in all three patients showed asymmetric hypertrophy and in two of the three patients, multiple sinusoids had replaced large segments of myocardial cells. The left ventricular free wall myocardium and the walls of the great arteries were unremarkable. Our data indicate that myocardial depletion involving the right ventricular free wall and the ventricular septum and its replacement by sinusoids and fibroelastic tissue occur not only in cases of absent pulmonary valve with tricuspid atresia but also in cases of absent pulmonary valve with tricuspid stenosis. The degree of myocardial depletion varies and is more severe when the tricuspid valve is atretic.

scholarly journals Limitation of heart growth in neonatal piglets by simvastatin and atorvastatin: comparison with pravastatin

2001 ◽  
Vol 280 (6) ◽  
pp. H2746-H2751 ◽  
Author(s):  
Kumi Satoh ◽  
Fumiyo Shirota ◽  
Takahiko Tsunajima ◽  
Cathy J. Beinlich ◽  
Howard E. Morgan ◽  
...  
Keyword(s):  
Map Kinase ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Free Wall ◽  
Left Ventricular Free Wall ◽  
Right Ventricular Free Wall ◽  
Neonatal Piglets ◽  
Mitogen Activated Protein ◽  
Residual Blood ◽  
The Right

The pig heart grows rapidly in the first few days after birth. We examined the effects of simvastatin, atorvastatin, and pravastatin on heart growth in piglets. After vehicle, 2 mg · kg−1 · day−1simvastatin, 2 mg · kg−1 · day−1atorvastatin, or 4 mg · kg−1 · day−1 pravastatin were administered orally for 6 days, the thoracic cavity was opened, and the heart was removed under pentobarbital sodium (30 mg/kg ip) anesthesia. The heart was perfused to remove residual blood. After the heart was blotted dry, the right and left ventricular free walls were dissected. Each free wall was weighed and used for determination of DNA, RNA, and protein concentrations and mitogen-activated protein (MAP) kinase activity. Simvastatin and atorvastatin resulted in smaller increases with age in the weight, concentrations of RNA and protein, and activity of MAP kinase in the left ventricular free wall, whereas pravastatin did not. The parameters of heart growth in the right ventricular free wall were not appreciably affected by either drug. The blood pressure and heart rate were not changed by the treatments. These results suggest that simvastatin and atorvastatin interfere with heart growth in neonatal piglets after birth, especially in the left ventricular free wall.

Regional myocardial blood flow and oxygen delivery in fetal, newborn, and adult sheep

1982 ◽  
Vol 243 (5) ◽  
pp. H729-H731 ◽  
Author(s):  
D. J. Fisher ◽  
M. A. Heymann ◽  
A. M. Rudolph
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Right Ventricular ◽  
Oxygen Delivery ◽  
Left Ventricular ◽  
Ventricular Free Wall ◽  
Regional Myocardial Blood Flow ◽  
Free Wall ◽  
Right Ventricular Free Wall ◽  
The Right

We measured and calculated their product, regional myocardial oxygen delivery, in unanesthetized, previously instrumented fetal, newborn, and adult sheep. In the fetus, blood flow and oxygen delivery were greater to the right ventricular free wall than to the left ventricular free wall. In the left ventricular free wall oxygen delivery increased significantly after birth and later decreased to a level in the adult that was similar to that of the fetus. There was a progressive decrease in oxygen delivery to the right ventricular free wall during the developmental period that we studied. Although the inner-to-outer blood flow ratio was significantly lower for the left and right ventricular free walls of the fetuses as compared with the newborns and adults, the ratio was greater than one in all three groups for both of the ventricular free walls. These data demonstrate that the changes that occur in the circulation after birth are associated with significant alterations in right and left ventricular myocardial blood flow and oxygen delivery, which most likely reflect changes in regional myocardial metabolic demands. In addition, there are further significant changes in regional myocardial blood flow during the transition from the newborn to adult hemodynamics.

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