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At least 73 records · Page 4Linked to original sources
PubMed1994

[Effect of left heart bypass on right ventricular function in normal and acute heart failure dogs--an application of the conductance catheter to the right ventricle].

We investigated right ventricular function during left heart bypass (LHB) with 18 mongrel open-chest dogs, in normal and acute heart failure (AHF) dogs which underwent aortic cross clamp. Left ventricular unloading was completely accomplished with a centrifugal pump. For more accurate evaluation of right ventricular volume, conductance catheter was employed to assess right ventricular function. Analysis were performed with right ventricular pressure-volume curve which was changed by transient volume loading on right ventricle. And right ventricular properties with and without LHB were compared by the use of load independent parameters as follows. Right ventricular systolic property was evaluated by maximum elastance (Emax) and stroke work-end-diastolic volume relation (SW/EDVR), and its diastolic function was evaluated by end-diastolic pressure-volume relation (EDP/VR). Overall right ventricular performance was assessed by stroke work-end-diastolic pressure relationship (SW/EDPR). In the normal heart, only a parallel shift to the right in EDP/VR and SW/EDVR was noted without any significant changes in slope with LHB. On the other hand, in AHF dogs, the slope of SW/EDVR and SW/EDPR were increased from 0.14 +/- 0.08 to 0.18 +/- 0.08 (p < 0.05), from 0.22 +/- 0.15 to 0.34 +/- 0.19 (p < 0.01), respectively, and the curve of EDP/VR was shifted right and downward. These result suggested that decompression of the left ventricle and septal shifting by LHB provided good diastolic compliance and afterload unloading of the right ventricle, and these effects had a more significant role in acute heart failure than in the normal heart.

Acute Disease↗
PubMed1997

Milrinone improves pulmonary hemodynamics and right ventricular function in chronic pulmonary hypertension.

BACKGROUND: Right ventricular failure after cardiac transplantation is commonly related to preexisting recipient pulmonary hypertension. This study was designed to investigate the effects of intravenous milrinone on pulmonary hemodynamic indices and right ventricular function in a canine model of monocrotaline pyrrole-induced chronic pulmonary hypertension. METHODS: Eight mongrel dogs underwent pulmonary artery catheterization to measure right-sided hemodynamic indices before and 6 weeks after a right atrial injection of monocrotaline pyrrole. Six weeks after injection, all hearts were instrumented with a pulmonary artery flow probe, ultrasonic dimension transducers, and micromanometers. Data were collected at baseline and after milrinone infusion. RESULTS: Six weeks after monocrotaline pyrrole injection, significant increases in the pulmonary artery pressure and pulmonary vascular resistance were observed. Milrinone led to significant increases in right ventricular function as well as significant improvements in pulmonary vascular resistance, pulmonary blood flow, and left ventricular filling. CONCLUSIONS: This investigation demonstrates the well-known hemodynamic and inotropic effects of milrinone which, in the setting of monocrotaline pyrrole-induced pulmonary hypertension, were also associated with significant increases in pulmonary blood flow and left ventricular filling.

Animals↗
PubMed1986

[Right ventricular function in occlusion of the right coronary artery].

Hemodynamic studies at rest and under volumetric loads were carried out in 10 dogs before and after the ligation of the right coronary artery with the closed pericardium. The ligation of the right coronary artery resulted in hemodynamic signs of depressed right-ventricular function: decreased systolic blood pressure and elevated end diastolic pressure, combined with the functional curve's downward shift to the right. Total cardiac performance (minute output and mean systemic flow pressure) was also reduced. It is suggested that depressed right-ventricular myocardial systolic function in infarction may be important for the development of the clinical low minute volume syndrome. Its pathophysiological mechanism and clinical implications are discussed.

Animals↗
PubMedDate not supplied

[Cardiac right ventricular function and hemodynamics during resection of the lungs].

Right-ventricular function and hemodynamics were studied in 48 patients during resections of the lungs (lobectomy and pneumonectomy) under total noninhalation anesthesia. Approaches to compensation of circulation in resection of different volume of lung tissue were determined. The leading role of the diastolic function of the right heart ventricle in realization of hemodynamic response in pneumonectomy is revealed. Volumetric monitoring of right-ventricular function during extensive lung resections is highly informative.

Anesthesia, General↗
PubMed1999

Immediate and delayed effects of successful percutaneous transvenous mitral commissurotomy on global right ventricular function in patients with isolated mitral stenosis.

Global right ventricular function of the pressure-overloaded right ventricle in patients with mitral stenosis and pulmonary hypertension after successful percutaneous transvenous mitral commissurotomy (PTMC) has not been well-defined. With the use of a recently developed Doppler method for estimating right ventricular function in human beings, we studied 25 consecutive patients with isolated rheumatic mitral stenosis before, immediately after (mean, 40+/-12 h) and at a mean follow-up of 11.5 months after PTMC. Immediately after percutaneous mitral commissurotomy, there was a significant increase in mitral valve area (P = 0.000017) along with a decrease in mean pulmonary pressure (P = 0.001). The index was not affected immediately after successful PTMC (0.70+/-0.25 vs., 0.58+/-0.18; P = 0.06); however, at follow-up of about one year, the index showed a significant decrease (0.697+/-0.28 vs. 0.380+/-0.13; P = 0.0008, n = 24). The change in the index was characterised by a significant prolongation of the right ventricular ejection time, with a decrease in the isovolumic intervals. The Doppler index of combined right ventricular function was significantly correlated to the mean pulmonary artery pressure (r = 0.695, P<0.001) and systolic pulmonary artery pressure (r = 0.60, P = 0.007) before PTMC and also immediately after the procedure; however, at follow-up, the index had no correlation with the Doppler estimated pulmonary artery systolic pressure (r = 0.07). Despite a larger mitral valve area following PTMC, right ventricular isovolumic indices remain abnormal on mid-term follow-up, although global function tends to normalise in two-thirds of the patients.

Adult↗
PubMed1985

[Measurement of right systolic time intervals in complete transposition of the great vessels. Value in the surveillance of ventricular function].

Right ventricular function was regularly assessed pre- and postoperatively by measuring right systolic time intervals at the aortic valve in 21 children with complete transposition of the great arteries. Twenty children underwent "physiological" surgical correction (Senning procedure) and one child with right ventricular hypokinesia underwent detransposition of the arteries. The mean value of the right ventricular pre ejection/ejection period ratio was 0.40 +/- 0.05; this was independent of age and no significant difference was observed between the pre- and postoperative periods (0.41 +/- 0.06 vs 0.39 +/- 0.04) at least with a maximum follow-up of 5 years. This index allows early diagnosis of right ventricular dysfunction and therefore helps to orientate the choice between "physiological" or "anatomical" surgical correction.

Child, Preschool↗
PubMed2006

MDCT of right ventricular function: impact of methodologic approach in estimation of right ventricular ejection fraction, part 2.

OBJECTIVE: The purpose of this study was to evaluate the impact of the methodologic approach for MDCT estimation of right ventricular ejection fraction (RVEF). MATERIALS AND METHODS: In 49 consecutive patients (30 men, 19 women; mean age, 59 years) known to have or suspected of having right ventricular (RV) dysfunction secondary to pulmonary disease, 16-MDCT of the heart was performed after standard CT angiographic examination of the entire thorax, with determination of RVEF by two reviewers who had limited experience in cardiac CT. The reconstruction windows were determined using the ECG tracing (reviewer 1) or using transverse test images obtained in 5% steps through the entire R-R interval showing the largest and smallest RV cavity areas (reviewer 2). After manual segmentation of the ventricular cavity on diastolic and systolic short-axis reformations by each reviewer, the end-diastolic and end-systolic RV volumes were calculated, with subsequent determination of the RVEF. CT results were compared with those of equilibrium radionuclide ventriculography. RESULTS: Agreement between the two methods for determining the end-systolic and end-diastolic phases was observed in 61% of cases (n = 30) for the systole and 59% of cases (n = 29) for the diastole. Discordant selections were observed in 39% of cases (n = 19) for determination of the systole and in 41% of cases (n = 20) for determination of the diastole, ranging from 5% to 15% of the R-R interval, suggesting that selection of the reconstruction window on the ECG tracing does not differ significantly from that obtained by the visual analysis of transverse test images. Focusing on the 59 common selections of the reconstruction windows made by the two reviewers, no statistically significant differences were found in the determination of mean (+/- SD) end-diastolic volumes (reviewer 1, 176.21 +/- 67 mL vs reviewer 2, 175.55 +/- 71.24 mL; p = 0.98) and end-systolic (reviewer 1, 97.3 +/- 26.49 mL vs reviewer 2, 96.33 +/- 65.72 mL; p = 0.65), suggesting the lack of operator dependence in the manual-contour drawing process. No significant difference was found between the mean values of RVEF obtained by each reviewer with MDCT and equilibrium radionuclide ventriculography, and there was excellent interobserver agreement with MDCT (intraclass correlation coefficient, 0.86). Using a Bland-Altman approach, the limits of concordance between the two reviewers ranged between -10.2 and 10.9. The mean absolute percentage error for measuring RVEF between the two reviewers was 9.7%. A moderate agreement was found between RVEFs obtained on CT by each reviewer and scintigraphy (intraclass correlation coefficients, 0.76 for reviewer 1 and 0.64 for reviewer 2). CONCLUSION: These results show that RVEF can be accurately assessed with ECG-gated MDCT using commercially available software.

Adult↗
PubMed2005

Evaluation of right ventricular function in patients with thyroid dysfunction.

BACKGROUND: Thyroid gland dysfunction affects the structure and function of the heart. Tissue Doppler echocardiography is a new technique, and it has been used frequently in the evaluation of ventricular function. In the present study, right ventricular function was assessed in patients with overt or subclinical hypothyroidism and hyperthyroidism and in healthy subjects using the tissue Doppler method, and results were compared. PATIENTS AND METHODS: 20 healthy subjects and 63 patients diagnosed with overt and subclinical hypothyroidism and hyperthyroidism were included in the study. Annular and myocardial systolic peak velocities, early and late diastolic peak velocities, precontraction, total contraction and relaxation times of the right ventricle were recorded by tissue Doppler echocardiography. The results of the patients were compared to those of the controls. RESULTS: Myocardial systolic velocity was significantly higher in patients with hyperthyroidism. Annular and myocardial late diastolic velocities were found to be significantly lower in patients with overt hypothyroidism. Annular precontraction time was increased in patients with overt and subclinical hypothyroidism. Myocardial precontraction time was decreased in patients with hyperthyroidism, and increased in patients with overt hypothyroidism patients. Annular relaxation time was increased in patients with overt hypothyroidism. CONCLUSIONS: Right ventricular function is affected in patients with thyroid diseases. The tissue Doppler technique is a suitable tool to detect impairments in right ventricular function. There is a significant correlation between serum thyroid hormone levels and right ventricular velocities and time intervals.

Adult↗
PubMed1991

The effect of acute hypoxia on right ventricular function in healthy adults.

Right ventricular ejection fraction and right ventricular volumes were derived in 12 healthy male subjects using krypton-81m equilibrium radionuclide ventriculography whilst subjects breathed 30% (high inspired oxygen) and then 8-12% oxygen in nitrogen mixture (hypoxia). 'Physiological' tricuspid valve regurgitation was identified in 7 of the subjects by Doppler echocardiography, and right ventricular peak systolic pressure was estimated during high inspired oxygen and during hypoxia. Mean right ventricular peak systolic pressure was 24.1 +/- 3.3 mmHg during high inspired oxygen and increased to 41.3 +/- 8.4 mmHg during hypoxia (P less than 0.01). Mean right ventricular ejection fraction was 0.612 +/- 0.075 during high inspired oxygen and was unchanged at 0.590 +/- 0.073 during hypoxia. There was no significant change in right ventricular end-diastolic volume or stroke volume in response to hypoxia. The systolic performance of the normal right ventricle is well-maintained during an acute rise in afterload induced by hypoxia.

Acute Disease↗
PubMed1995

[Right ventricular function in patients with obstructive sleep apnea].

Obstructive sleep apnea often affects the cardiovascular system. So far, only few data are available on its influence on the function of the right ventricle that can be evaluated by gated radionuclide ventriculography. This technique was performed on 68 patients with polysomnographically verified obstructive sleep apnea. 27.9% of the patients showed an impairment of right ventricular function. There was no correlation between right ventricular function and degree of obstructive sleep apnea or pulmonary artery pressures--as evaluated by right heart catheterization. Gated radionuclide ventriculography thus seems to be suitable for early detection of pathological effects of obstructive sleep apnea on the function of the right ventricle.

Adult↗
PubMed1988

Effect of positive end-expiratory pressure on right ventricular performance. Importance of baseline right ventricular function.

Thirty-six patients with diverse baseline right ventricular function were evaluated during incremental positive end-expiratory pressure (PEEP) application. Right heart pressures, cardiac output, right ventricular ejection fractions, and ventricular volumes were obtained at each PEEP level. Right ventricular peak systolic pressure-end-systolic volume relations were analyzed as an index of contractile function. Patients with severely depressed baseline right ventricular ejection fractions (30 percent or less) had an increase in end-diastolic (270 +/- 74 to 391 +/- 76 ml, 0 to 20 cm water (H2O) PEEP, p less than 0.05) and end-systolic volumes (210 +/- 70 to 321 +/- 70 ml, 0 to 20 cm H2O PEEP, p less than 0.05). These patients also had a decline in estimated right ventricular contractile function at 20 cm H2O PEEP as estimated by the slope of systolic pressure-volume relations (0.12 to 0.04 mm Hg/ml, 0 to 15 and 15 to 20 cm H2O PEEP, respectively, p less than 0.05). Patients with normal (40 percent or more) or moderately depressed (31 to 40 percent) baseline right ventricular ejection fractions had no change in right ventricular volumes or estimated contractile function. Therefore, the effect of PEEP on right ventricular function differs depending on the baseline right ventricular ejection fraction.

Adult↗
PubMed2006

Right ventricular function predicts transplant-free survival in idiopathic dilated cardiomyopathy.

BACKGROUND: Right ventricular function may be reduced in patients with idiopathic dilated cardiomyopathy (IDC). The prognostic implications of right ventricular dysfunction have not been investigated in this group of patients. METHODS: In a series of 120 consecutive patients with IDC [defined as a left ventricular ejection fraction (LVEF) < 55%, normal coronary arteries and no other causes for left ventricular dysfunction], right ventricular function was prospectively evaluated by means of angiocardiography at the time of catheterization. A head-to-head comparison of ventricular volumes, ejection fraction, end-diastolic pressure, stroke work index and end-systolic pressure/volume ratio of the left and right ventricle was performed according to the Cox's proportional hazard method for the pre-defined end-point of transplant-free survival. RESULTS: In the study population, LVEF was 31 +/- 11% and right ventricular ejection fraction (RVEF) was 34 +/- 10%. After a mean follow-up of 30 months (range 12-120 months), 26 patients died (22%) and 14 (12%) underwent heart transplantation. At univariate analysis, all the above mentioned parameters were significantly (P < 0.0001) associated with outcome except left and right ventricular end-systolic pressure/volume ratio. At multivariate analysis, independent predictors of transplant-free survival were RVEF (P = 0.001), right ventricular stroke work index (P = 0.015), right ventricular end-diastolic volume (P = 0.034) and left ventricular end-diastolic volume (P = 0.048), but not LVEF. The same relation holds true considering the end point of total mortality. CONCLUSIONS: Parameters of right ventricular function are strong predictors of survival in IDC, even in patients enrolled over a wide range of LVEFs. The present study suggests that right ventricular function should be evaluated in patients with IDC. A large non-invasive based study on right ventricular function in IDC appears to be warranted.

Adult↗
PubMed1986

Right ventricular function in the hypoxaemic fetal sheep.

Right ventricular function was investigated in seven fetal sheep (125-130 days gestation) hypoxaemic at a mean of 5 days postoperation, and were compared to nine normoxaemic fetal sheep of the same gestation. Arterial O2 and CO2 tensions, pH, and haematocrit values for the hypoxaemic and normoxaemic fetuses were 15.6 +/- 1.0 vs. 20.6 +/- 1.8 torr, 49.4 +/- 4.1 vs. 46.1 +/- 1.6 torr, 7.38 +/- 0.02 vs. 7.39 +/- 0.02, and 29 +/- 7.5 vs. 31 +/- 5.3%, respectively. Right ventricular output and stroke volume were similar in the two groups, 241 +/- 57 vs. 247 +/- 75 ml X min-1 X kg-1 and 1.5 +/- 0.4 vs. 1.5 +/- 0.4 ml X kg-1, respectively. Filling and afterload pressures were also similar in the hypoxaemic and normoxaemic fetuses with right atrial pressure of 3.0 +/- 1.0 vs. 3.7 +/- 1.2 mmHg, and arterial pressure of 42 +/- 5 vs. 43 +/- 4 mmHg, respectively. Ventricular function curves were produced by rapid withdrawal and re-infusion of fetal blood producing curves with a steep ascending limb and a plateau phase. The breakpoint joining the limbs of the control function curve for the hypoxaemic and normoxaemic fetuses were right atrial pressure 2.9 +/- 1.0 vs. 3.4 +/- 1.2 mmHg and a stroke volume of 1.5 +/- 0.5 vs. 1.5 +/- 0.4 ml X kg-1, respectively. Linear regression of stroke volume against arterial pressure from 30-90 mmHg during infusions of nitroprusside and phenylephrine at right atrial filling pressures greater than breakpoint was stroke volume = 0.018 ml X kg-1 X mmHg-1 arterial pressure +/- 2.25 ml X kg-1. This equation is not different from that calculated in normoxaemic fetuses, and demonstrates that the fetal right ventricle is quite sensitive to changes in arterial pressure. These data indicate that reduction in fetal oxygen content by an estimated 40% does not affect fetal right ventricular function.

Animals↗
PubMed1994

Does septal position affect right ventricular function during left ventricular assist in an experimental porcine model?

Right ventricular (RV) failure has been a major problem with patients supported by left ventricular (LV) assist devices (LVADs). To assess the importance of interventricular septal (IVS) position as a mechanism of RV failure, 7 Yorkshire pigs underwent implantation of a Thoratec LVAD. RV function was assessed before and during LVAD operation under differing conditions: (1) with an LV intraventricular latex balloon inflated or deflated to alter IVS position and (2) with and without pulmonary artery (PA) constriction to assess the effect of changes in afterload. RV stroke work, RV dP/dt, and RV end-diastolic length did not change significantly with LVAD operation or with changing afterload conditions. Septal shift was documented as a change in LV shape index (LVSI) calculated using echocardiography. LVSI decreased by 11% when the LVAD was turned on, indicating leftward shifting of the IVS (P = .01). During LVAD support and increased RV afterload, the LVSI decreased by 14.8% (P = .02). RV cardiac output decreased somewhat during LVAD support. However, RV output was worst when the septal position was normalized using the inflated intraventricular balloon during increased RV afterload (P = .05). Unloading by the LVAD of the left ventricle results in a leftward shift of the interventricular septum, which does not appear to adversely affect RV function. However, during conditions of increased RV afterload, septal shifting may be beneficial to RV function.

Animals↗
PubMed1994

The cardiovascular changes associated with equipotent anaesthesia with either propofol or isoflurane. Particular emphasis on right ventricular function.

The differences in effects of anaesthetic agents on right ventricular function have not been studied. We have developed a cross-over study design to compare the effects of propofol and isoflurane on cardiac and specifically right ventricular function. Ten patients were anaesthetised with equivalent MAC of isoflurane to MIR of propofol. After measurements had been taken on the randomly assigned first agent the patients were crossed over to the other agent and measurements were repeated. Cardiac function was assessed using a pulmonary artery catheter with a fast response thermistor. There were no differences in heart rate or blood pressure between the two agents suggesting that equivalent anaesthetic doses had been given. There were significantly (P < 0.05) higher cardiac output (4.0 to 4.5 l.min-1), right ventricular ejection fraction (35.1 to 39.4%), stroke volume (35.4 to 39.6 ml) and right ventricular end-diastolic volume index (102 to 110 ml.m2-1) with propofol compared to isoflurane. We conclude that propofol results in improved right ventricular performance compared to isoflurane. We have also shown that anaesthetic agents can be compared using a cross-over study design, and have demonstrated that MAC of isoflurane and MIR of propofol can be directly compared. We suggest that propofol may be a more suitable agent than isoflurane for anaesthesia in patients who may already have impaired right ventricular function and in whom maintaining high cardiac output may be beneficial.

Aged↗
PubMed1995

Comparison of echocardiographic methods with magnetic resonance imaging for assessment of right ventricular function in children.

Assessment of right ventricular (RV) function is clinically relevant in the follow-up of various forms of congenital heart disease. Agreement on the value of different echocardiographic approaches for this purpose is lacking. Magnetic resonance imaging (MRI) provides dimensionally accurate RV volumes and ejection fraction. Transthoracic 2-dimensional echocardiography from 3 different views and gradient-echo tomographic MRI were performed in 16 children with congenital heart disease and 17 age-matched healthy children. RV volumes and ejection fraction were calculated with 5 mono- and biplane area-length and multiple-slice echocardiographic methods. Adequate MRI and echocardiographic apical 4-chamber images could be obtained in all 33 children. The best correlation between MRI and echocardiographic volumes was with the biplane pyramidal approximation method. End-diastolic volume by MRI was 92 +/- 27 ml: systematic difference with echocardiography was +14 +/- 16 ml (r = 0.86). End-systolic volume by MRI was 33 +/- 13 ml: systematic difference with echocardiography was -4 +/- 7 ml (r = 0.82). Ejection fraction by MRI was 65 +/- 8%: systematic difference with echocardiography was +5 +/- 7% (r = 0.72), using monoplane ellipsoid approximation. For all echocardiographic methods, significant effects of RV geometry were noted. Echocardiographic mono- and biplane area-length and multiple-slice calculations demonstrated moderate correlation and significant systematic errors compared with MRI-derived RV volumes. Echocardiographic results were influenced by RV geometry. The relatively simple monoplane area-length method provides ejection fraction results acceptable for clinical practice; results are not improved by more complex biplane and/or multislice methods.

Adolescent↗
PubMed2005

Quantifying regional right ventricular function in tetralogy of Fallot.

Right ventricular (RV) function is notoriously difficult to quantify. Patients with tetralogy of Fallot (TOF) have decreased systolic performance. We measure regional RV performance using MRI with 1-dimensional myocardial tissue tagging. By tagging cine-MRI in two views, we measured regional shortening in 12 regions throughout the RV. We image 32 pediatric patients: 21 normal patients and 11 patients with repaired TOF. We establish a normal range for each RV region. TOF patients have decreased shortening on a region-by-region basis. We conclude that regional RV performance can be measured using this technique, and that decreased performance can be demonstrated in TOF patients.

Adolescent↗