Significant left ventricular contribution to right ventricular systolic function

1991 ◽  
Vol 261 (5) ◽  
pp. H1514-H1524 ◽  
Author(s):  
R. J. Damiano ◽  
P. La Follette ◽  
J. L. Cox ◽  
J. E. Lowe ◽  
W. P. Santamore

To examine the importance of systolic ventricular interdependence on right ventricular function, we used a unique electrically isolated right ventricular free wall preparation. Double-peaked waveforms for right ventricular pressure and pulmonary arterial blood flow occurred over a wide range of pacing intervals between the left and right ventricles. One component of the waveforms could be directly related to right ventricular free wall contraction, whereas the other component was directly related to left ventricular and septal contraction. For left ventricular pressure, the left ventricular component was significantly larger than the right ventricular free wall component (92.7 +/- 3.2 vs. 7.3 +/- 3.2% peak-to-peak value, P less than 0.01). For right ventricular pressure, the left ventricular and septal component was significantly greater than the right ventricular component (63.5 +/- 10.9 vs. 36.5 +/- 10.9% peak-to-peak value, P less than 0.05). Similarly, for pulmonary arterial blood flow, the left ventricular component was significantly greater than the right ventricular component. When right ventricular free wall pacing stopped in diastole, 68 +/- 4% of right ventricular systolic pressure and 80 +/- 4% of pulmonary flow were obtained in the subsequent beat. The results of this study indicate that left ventricular contraction is very important for right ventricular developed pressure and volume outflow.

2000 ◽  
Vol 3 (4) ◽  
pp. 353-366 ◽  
Author(s):  
Silvio Litovsky ◽  
Michael Choy ◽  
Jeanny Park ◽  
Mark Parrish ◽  
Brenda Waters ◽  
...  

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.


1982 ◽  
Vol 243 (5) ◽  
pp. H729-H731 ◽  
Author(s):  
D. J. Fisher ◽  
M. A. Heymann ◽  
A. M. Rudolph

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.


1987 ◽  
Vol 252 (5) ◽  
pp. H933-H940 ◽  
Author(s):  
W. C. Little ◽  
R. C. Park ◽  
G. L. Freeman

We investigated the effects of coronary artery occlusion and pacing from ventricular sites on the relation of the maximum rate of rise of left ventricular pressure (dP/dtmax) to the end-diastolic volume (VED) in dogs previously instrumented to measure left ventricular pressure and to determine left ventricular volume from three ultrasonically measured dimensions. The dP/dtmax-VED relation was generated by vena caval occlusion and compared with the simultaneously produced end-systolic pressure-end-systolic volume (PES-VES) relation. The dP/dtmax-VED relation was described by a straight line during all conditions. Occlusion of the left circumflex coronary artery produced a rightward shift of the dP/dtmax-VED relation, increasing the volume intercept by 11.3 +/- 5.3 (SD) ml (P less than 0.05). Compared with atrial pacing, the dP/dtmax-VED relation was shifted to the right with the volume intercept increasing by 4.8 +/- 4.4 ml (P less than 0.05) during pacing from the right ventricular free wall, 3.7 +/- 5.0 ml (P less than 0.05) during pacing from the right ventricular apex, and 3.7 +/- 2.4 ml (P less than 0.05) during pacing from the left ventricular free wall. Similar increases were observed in the volume intercepts of the PES-VES relations during coronary occlusion or ventricular pacing. These results are consistent with the predictions of the time-varying elastance model and support its use as a conceptual framework to understand left ventricular performance during isovolumic contraction and at end systole, both in the normal ventricle and the ventricle with regional abnormalities of contraction.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260456
Author(s):  
Ryotaro Asano ◽  
Takeshi Ogo ◽  
Yoshiaki Morita ◽  
Akiyuki Kotoku ◽  
Tatsuo Aoki ◽  
...  

Background Right ventricular function is an important prognostic marker for pulmonary arterial hypertension. Native T1 mapping using cardiovascular magnetic resonance imaging can characterize the myocardium, but accumulating evidence indicates that T1 values of the septum or ventricular insertion points do not have predictive potential in pulmonary arterial hypertension. We aimed to elucidate whether native T1 values of the right ventricular free wall (RVT1) can predict poor outcomes in patients with pulmonary arterial hypertension. Methods This retrospective study included 30 patients with pulmonary arterial hypertension (median age, 45 years; mean pulmonary artery pressure, 41±13 mmHg) and 16 healthy controls (median age, 43 years) who underwent native T1 mapping. RVT1 was obtained from the inferior right ventricular free wall during end systole. Results Patients with pulmonary arterial hypertension had significantly higher native RVT1 than did controls (1384±74 vs. 1217±57 ms, p<0.001). Compared with T1 values of the septum or ventricular insertion points, RVT1 correlated better with the effective right ventricular elastance index (R = −0.53, p = 0.003), ventricular-arterial uncoupling (R = 0.46, p = 0.013), and serum brain natriuretic peptide levels (R = 0.65, p<0.001). Moreover, the baseline RVT1 was an accurate predictor of the reduced right ventricular ejection fraction at the 12-month follow-up (delta -3%). RVT1 was independently associated with composite events of death or hospitalization from any cause (hazard ratio = 1.02, p = 0.002). Conclusions RVT1 was predictive of right ventricular performance and outcomes in patients with pulmonary arterial hypertension. Thus, native T1 mapping in the right ventricular free wall may be an effective prognostic method for pulmonary arterial hypertension.


2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
A Stoylen ◽  
H E Molmen ◽  
H E Dalen

Abstract Background Displacement (MAPSE) and peak systolic velocity (S") of the various parts of the mitral annulus differ. Also, both indices are higher in the right ventricular free wall. We aimed to investigate the relations between wall motion, wall lengths and sites in the left ventricle, as well as comparing to the right ventricle to assess the influence on systolic deformation of the AV-plane. Methods The HUNT study examined 1266 subjects without evidence of heart disease from a mixed urban/rural population of North Trøndelag county, S", linear diastolic left ventricular annulus to apex distance (WL) and MAPSE was measured in the septal, anterior, lateral and inferior points of the mitral annulus. Intra individual variance and relative variance (variance / mean) of S" and MAPSE was calculated and compared to the same variance of the values normalised for wall length (S"/WL and MAPSE/WL). Results Wall lengths, velocities and MAPSE are shown in figure 1. Wall lengths were associated with both MAPSE and S". Both wall lengths and motion were greatest in the free walls of the LV, but smallest in the septal parts of the AVplane. Variances are shown in table 1. Even if intra-individual variances are larger for S" than MAPSE, relative variance for both decreased by 80 - 90% when normalised for wall length. Conclusion There is an intra-individual variability of MAPSE and S" of the LV, corresponding to WL, when the values normalised for WL most of the variability disappears. Intra individual variability of strain and strain rate per wall is less than MAPSE and S" as shown earlier. As the apex is located centrally, walls corresponding to the free walls are longer than those closest to the septum, thus motion and wall length are both greatest corresponding to the LV free walls. Motion of the right ventricular free wall was higher than the LV free wall; TAPSE 2.8 cm, and S" 12.6 cm/s as shown previously. The relation of TAPSE and S" of the right ventricle to wall length will be different, as the afterload in the RV is far less. But as both lateral parts of the AV plane move more than the centre, givinga systolic bending of the AV-planealso as the central part of the AV-plane is centrally anchored to the large arteries as shown in fig. 1. Table 1 WL (cm) MAPSE (cm) MAPSE / WL (% points) S" (cm/s) S" / WL (/s) Mean of 4 walls 9.5 1.6 0.16 8.4 0.87 Variance 0.04 0.04 0.0004 1.2 0.01 Relative variance (%) 2.8 2.7 0.25 12.1 1.4 Wall lengths (WL), displacement(MAPSE), Systolic velocity (S") and mAPSE and S" normalised for WL. Means and intra individual variances. Abstract P1744 Figure. Fig. 1


2006 ◽  
Vol 26 (2) ◽  
pp. 109-115 ◽  
Author(s):  
Kenneth C. Bilchick ◽  
Sudip K. Saha ◽  
Ed Mikolajczyk ◽  
Leslie Cope ◽  
Will J. Ferguson ◽  
...  

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.


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