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PubMed1993

[Current aspects in diagnosis of chronic cor pulmonale].

Pulmonary hypertension occurs frequently in patients with chronic obstructive lung diseases and contributes to a poor prognosis. Most common symptoms in addition to dyspnea, cough and expectoration are fatigue, syncopes, chest pain and peripheral oedema. No single non-invasive method such as lung function testing, blood gas analysis, ECG, chest x-ray, myocardial scintigraphy and isotopic radionuclide ventriculography is sufficiently reliable for predicting pulmonary hypertension. Only the combination leads to the diagnosis of pulmonary hypertension and cor pulmonale within acceptable limits. Echocardiography was found to be a reliable method of assessing right ventricular function. Doppler echocardiography is most useful with a specificity and sensitivity of about 80%. As "golden standard" cardiac catheterisation is still required for the measurement of pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) at rest and exercise.

Cardiac Catheterization↗
PubMed1995

Mechanisms of transplant right ventricular dysfunction.

OBJECTIVE: Right ventricular (RV) dysfunction remains the leading cause of early mortality after cardiac transplantation. The effect of brain death and subsequent hypothermic cardioplegic arrest and storage on subsequent post-transplant right ventricular function was examined. SUMMARY BACKGROUND DATA: Right ventricular dysfunction in the donor heart usually is attributed to failure of the donor right ventricle to adapt to the sudden increase in afterload (pulmonary vascular resistance) in the recipient. Strategies to improve ventricular mechanics in the postoperative period are aimed at reducing pulmonary vascular resistance with vasodilators or augmenting right ventricular contractility with inotropic agents. Events occurring in the donor heart (brain death, hypothermic cardioplegic arrest, and storage) also may be directly related to post-transplant RV dysfunction. METHODS: A canine model of brain death and orthotopic cardiac transplantation was used. A dynamic pressure-volume analysis of RV mechanics was performed using micromanometers and sonomicrometric dimension transducers. Systolic function was assessed by measurement of preload recruitable stroke work (PRSW). Brain death was induced in 17 dogs by inflation of an intracranial balloon. Right ventricular function then was assessed serially to 6 hours (PRSW). Right ventricular adrenergic beta receptor density and function was sampled at control and after 6 hours of brain death. The effect of cardioplegic arrest and hypothermic storage was assessed in a second group of 17 dogs, using the same instrumentation and method of RV analysis. RESULTS: A significant decrease in right ventricular PRSW occurred after brain death, with the average decrease being 37% +/- 10.4% from the control. The RV myocardial beta adrenergic receptor density did not significantly change (253 +/- 34 fmol/ng control vs. 336 +/- 54 fmol/ng after brain death). The adenylyl cyclase activity of the RV beta receptor was assessed and was not altered by brain death. Orthotopic transplantation after cardioplegic arrest and hypothermic storage significantly decreased RV PRSW from 23.6 +/- 2.0 x 10(3) erg to 13.5 +/- 1.4 x 10(3) erg. CONCLUSIONS: These data indicate that the donor right ventricle is exposed to factors significantly detrimental to its mechanical performance well before facing an increased afterload in the recipient. Strategies to reduce RV dysfunction associated with brain death and hypothermic storage could positively impact post-transplant survival.

Animals↗
PubMed1997

Configuration of linear dynamic cardiomyoplasty for hypoplastic right ventricle.

BACKGROUND: The purpose of this study is to determine feasibility of linear dynamic cardiomyoplasty with a briefly preconditioned latissimus dorsi in the experimental model simulating patch enlargement of the hypoplastic right ventricle. METHODS: In 8 mongrel dogs, a diminished right ventricular chamber was reconstructed with an extended pericardial patch. A left latissimus dorsi, preconditioned for 2 weeks (2 Hz) after a previous 2-week vascular delay period, was placed on the patch, with the muscle fiber oriented in parallel to the right ventricular long axis. RESULTS: Graft pacing with trained-pulses of 25 Hz at a 1:1 ratio showed significant augmentation of pulmonary flow and pressure (158% +/- 21%, 156% +/- 14%, respectively), contributing to restoring right ventricular function comparable with preoperative control, which was also confirmed by the right ventricular function curve and pressure-volume relationship analyzes. Continuous pacing was performed in 4 animals for 7 hours without evidence of muscle fatigue, implying feasibility of "working conditioning" after minimum preconditioning for this type of right heart assist. CONCLUSIONS: Linear latissimus dorsi myoplasty can restore normal right ventricular performance at a physiologic preload, and may provide a surgical option for the hypoplastic right ventricle.

Animals↗
PubMed1994

The role of right and left ventricular function in the ventilatory response to exercise in chronic heart failure.

BACKGROUND: Right ventricular function may be an important determinant of exercise capacity, peak oxygen consumption (VO2), and the ventilatory response to carbon dioxide production (VE/VCO2 relation) in patients with chronic heart failure (CHF). METHODS AND RESULTS: We studied the role of right ventricular function in CHF and also investigated the effects of absent right ventricular reserve in patients previously operated on with Fontan's procedure by measuring metabolic gas exchange during exercise in five groups of patients: (1) 10 patients who had previously undergone Fontan's procedure for congenital heart disease in whom the right ventricle is not functional; (2) 11 age-matched control subjects with dilated cardiomyopathy (DCM); (3) 15 age-matched normal subjects; (4) 42 patients with CHF; and (5) 16 age-matched control subjects. Left and right ventricular ejection fractions (LVEF and RVEF) were measured by radionuclide ventriculography in group 4. In the young subjects, the VE/VCO2 slope was lower in the control subjects than in the other two groups, being 24.4 +/- 4.3 against 33.3 +/- 6.6 in group 1 (P < .001) and 29.6 +/- 8.1 in group 2 (P < .05). The correlation between peak VO2 and VE/VCO2 was -0.80 (P = .005) in group 1 and -0.76 (P = .007) in group 2. In the older age groups, the VE/VCO2 slope was significantly greater (38.0 +/- 14.9 versus 25.4 +/- 3.7; P < .001) in the heart failure group (group 4). In neither control group was there a significant relation between peak VO2 and VE/VCO2 slope. In group 4, the relation between peak VO2 and VE/VCO2 was similar to that seen for groups 1 and 2. LVEF was 24.3 +/- 14.1%, and RVEF was 32.5 +/- 13.1%. There was no correlation between either RVEF or LVEF and peak VO2 or VE/VCO2 slope in the heart failure group. CONCLUSIONS: The relation between excessive ventilation and reduction in peak oxygen consumption is present in patients with no functioning right ventricle. RVEF is not a determining feature of either exercise capacity or the excessive ventilatory response in CHF.

Adult↗
PubMed2002

Right ventricular performance during left ventricular unloading conditions: the contribution of the right ventricular free wall.

AIM: Right ventricular (RV) dysfunction is a significant complication following implantation of left ventricular assist device (LVAD). However, RV performance after LVAD implantation remains unclear. We have studied the effects of preload and afterload on RV performance under left ventricular (LV) unloading. METHODS: Six adult mongrel dogs were subjected to cardiopulmonary bypass. RV preload and afterload were independently regulated. Dynamic pressure-length analysis of RV free walls was performed using micromanometer catheter and sonomicrometric dimension transducers. Global RV systolic function was evaluated by the relationship between stroke volume vs. end-diastolic length (EDL) or end-diastolic pressure (EDP). We also examined the afterload dependency of RV performance at constant stroke volume. RESULTS: Stroke volume vs. EDP and stroke volume vs. EDL demonstrated a linear relationship (r(2) = 0.849 +/- 0.147 and 0.776 +/- 0.121, respectively). At constant stroke volume, RV systolic peak pressure vs. EDL or EDP were shown to have a linear relationship (r(2) = 0.906 +/- 0.050 vs. 0.909 +/- 0.047, respectively). CONCLUSION: The Frank-Starling relationship for RV performance was shown in this animal model. Without interventricular interaction, RV preload is dependent on RV afterload.

Animals↗
PubMed1994

Left and right heart Doppler stress echo in congestive heart failure.

Doppler echocardiographic assessment of the left and right ventricular function at rest, during and 6 minutes after submaximal exercise was performed in 60 patients with a mean age of 43 +/- 11 years suffering from heart failure classified stage I-III according to the NYHA-criteria and 10 volunteers with a mean age of 36 +/- 9 years who served as a control group. At mitral (m) and tricuspid (t) valve early diastolic peak-flow velocity (VEm, VEt), atrial peak-flow velocity (VAm, VAt), speed-time integrals (Em, Et, Am, At) and the ratios (VE/VAm, VE/VAt, E/Am, E/At) were determined. The left ventricular end-diastolic diameter (LVEDD) and the right ventricular outflow tract (RVOT) were measured in addition. The left ventricular ejection fraction (LVEF) was decreased to < 36% in 9 patients (group 1). In 51 individuals LVEF was found to be > 35% but < 50% or LVEF was shown to be > 50% but VE/VAm-ratio was found to be < 1 (group 2). Out of all the determined parameters, VE/VAt, VEt and VAm during exercise were found to be the most sensitive parameters for the detection of early to advanced grade left heart failure.

Adult↗
PubMed2006

Evaluation of global and regional right ventricular systolic function in patients with pulmonary hypertension using a novel speckle tracking method.

This study sought to demonstrate that a novel speckle-tracking method can be used to assess right ventricular (RV) global and regional systolic function. Fifty-eight patients with pulmonary arterial hypertension (11 men; mean age 53 +/- 14 years) and 19 age-matched controls were studied. Echocardiographic images in apical planes were analyzed by conventional manual tracing for volumes and ejection fractions and by novel software (Axius Velocity Vector Imaging). Myocardial velocity, strain rate, and strain were determined at the basal, mid, and apical segments of the RV free wall and ventricular septum by Velocity Vector Imaging. RV volumes and ejection fractions obtained with manual tracing correlated strongly with the same indexes obtained by the Velocity Vector Imaging method in all subjects (r = 0.95 to 0.98, p < 0.001 for all). Peak systolic myocardial velocities, strain rate, and strain were significantly impaired in patients with pulmonary arterial hypertension compared with controls and were most altered in patients with the most severe pulmonary arterial hypertension (p < 0.05 for all). Pulmonary artery systolic pressure and a Doppler index of pulmonary vascular resistance were independent predictors of RV strain (r = -0.61 and r = -0.65, respectively, p < 0.05 for both). In conclusion, the new automated Velocity Vector Imaging method provides simultaneous quantitation of global and regional RV function that is angle independent and can be applied retrospectively to already stored digital images.

Echocardiography, Doppler↗
PubMed1993

[A case of constrictive pericarditis--adjuvant techniques of operation and evaluation of the perioperative cardiac function].

A 43-year-old male diagnosed as constrictive pericarditis with dyspnea, fatigability and substantial pericardial calcification on chest roentgenogram underwent pericardiectomy through median sternotomy. The heavily calcified pericardium which was adherent to the anterior and diaphragmatic surface of the heart was successfully resected by the combined use of ultrasonic surgical aspirator (CUSA) and argon beam coagulator (ABC). Intraoperative bleeding was minimal because the adhesion between the pericardium and myocardium, coronary arteries or inferior vena cava were easily dissected with CUSA. Intraoperative hemostasis was also satisfactory with ABC. Perioperative measurements of right ventricular ejection fraction were also effective in evaluating the right ventricular function.

Adult↗
PubMed2000

Complete transposition of the great arteries: surgical concepts for patients with systemic right ventricular failure following intraatrial repair.

One of the most serious late complications of the intraatrial baffle procedure (Mustard or Senning correction) in patients suffering from transposition of the great arteries, (TGA) is the late systemic right ventricular failure. Nearly all patients presenting with right ventricular dysfunction have severe associated tricuspid regurgitation. The surgical options for these patients include tricuspid valve reconstruction or replacement, staged conversion to the arterial switch operation and orthotopic heart transplantation. Review of 189 operative survivors who underwent the Mustard or Senning operation for TGA between 1970 and 1993 in our institution revealed 12 patients (6.3%) who died from severe systemic right ventricular dysfunction (mean follow-up 16+/-3.5 years), which was the most common cause of late death. All of them had concomitant severe tricuspid regurgitation. 7 patients (3.7%) died from sudden cardiac death. The actuarial survival at 10 years is 93% for simple TGA and 85% for TGA associated with ventricular septum defect or coarctation. At our institution, 4 adolescent or adult patients underwent tricuspid valve surgery; tricuspid valve replacement was performed in 2 patients and valve repair in 2 patients. In the mid-term follow-up, 2 of these patients died. Two additional patients underwent orthotopic heart transplantation, and one died on the waiting list. Staged conversion from the Senning/Mustard atrial repair to the arterial switch operation was initially reported by Mee. The procedure for pulmonary artery banding starts with inducing left ventricular reconditioning with subsequent arterial switch. The mortality of this two-staged procedure was as high as 20% to 30% in our early experience, and some of the candidates underwent heart transplantation. Tricuspid valve repair or replacement do not improve right ventricular function in patients with a failing right ventricle following the Mustard/Senning operation. Staged conversion to arterial switch may improve right ventricular function by decreasing the work load of the right ventricle and provides anatomic repair with left ventricle-to-aorta continuity. Orthotopic heart transplantation is the only alternative if the left ventricle does not respond to pulmonary artery banding.

Actuarial Analysis↗
PubMedDate not supplied

Effect of artificial lung compliance on right ventricular load.

Artificial lungs may serve as transplant alternatives to patients with respiratory failure. To provide a pulmonary replacement, the device cannot significantly alter right ventricular afterload. We sought to characterize cardiac load using a prototype artificial lung as a pulmonary replacement. An artificial lung was implanted into 13 adult sheep, 7 using a noncompliant original prototype and 6 using a modified device with a compliance chamber. Inflow was from the pulmonary artery and outflow into the left atrium. Pulmonary impedance was determined and pulse wave reflections analyzed. Resistance was similar in the original prototype artificial lung and in the native pulmonary circulation (3.0 vs 3.2 Woods units, p = 0.5). First harmonic impedance was significantly increased in the original prototype artificial lung (0.4 vs 5.9 Woods units, p < 0.01). High-amplitude pulse wave reflections were identified and right ventricular function was altered. The addition of compliance to the artificial lung reduced impedance at the first harmonic (5.9 vs 1.9 Woods units, p < 0.01), decreased the amplitude of pulse wave reflections, and normalized right ventricular function. A low-resistance but noncompliant artificial lung increases pulmonary impedance and alters right ventricular function. Addition of a compliance chamber reduces pulse wave reflections and normalizes ventricular function.

Animals↗
PubMed2000

Effects on dogs of surface-induced hypothermia and rewarming on the right heart function and pulmonary circulation.

Hypothermia is commonly found in accidents on land and at sea, yet its pulmonary circulatory effects have not been studied before. To study the effects of hypothermia on the right heart function and pulmonary circulation, cardiac catheterization was carried out on nine anaesthetized beagle dogs. The dogs were cooled between ice bags until the temperature in the pulmonary artery was 25 degrees C and then rewarmed using a heating box especially constructed for this purpose. Heart rate decreased significantly (P < 0.01) during cooling. Cardiac output also diminished mainly because of decreased heart rate. Total pulmonary resistance increased in the cold (P < 0.05) and returned to the initial level during rewarming. The peak rate of increase in pressure (dP/dtmax) of the right ventricular pressure curve did not show any significant change. Retardation in relaxation in hypothermia was indicated by an increase (P < 0.01) in the peak negative dP/dt of the right ventricular pressure curve. According to our results, the contraction rate did not change, but the relaxation rate decreased significantly during cooling. No signs of heart failure were observed and all parameters returned to normal during rewarming. In conclusion, right ventricular function was not compromised even during deep hypothermia.

Animals↗
PubMed2005

Analysis of atrial and ventricular performance by tissue Doppler imaging in patients with atrial septal defects before and after surgical and catheter closure.

OBJECTIVE: To compare the effects of surgical and device closure of atrial septal defects on atrial and ventricular performance assessed by the novel tissue Doppler derived strain rate. BACKGROUND: Despite the increasing number of transcatheter closures, there is no information comparing the effect of the transcatheter closure technique on atrial performance with that of conventional surgery. Tissue Doppler derived strain rate can effectively quantify local myocardial function independent of the overall heart motion. DESIGN AND PATIENTS: Twenty-four patients [aged 21.5 (6-70) years] with isolated atrial septal defect of the secondum type before and 1 week after surgical (n = 12) or Amplatzer Septal Occluder closure (n = 12) and 30 healthy controls [aged 26.0 (2-58) years] were studied. Atrial and ventricular strain rate curves were assessed in the middle of their corresponding lateral walls in an apical four-chamber view. The systolic, early diastolic, and late diastolic strain rates peaks were measured. RESULTS: Compared to preclosure condition, the right atrial late diastolic (P < 0.01), right ventricular systolic (P < 0.01), right ventricular early diastolic (P < 0.01), and left atrial late diastolic peak (P < 0.01) strain rates were reduced after surgery but not after Amplatzer Septal Occluder closure. The LV parameters did not significantly differ before and after atrial septal defect closure by either technique. CONCLUSIONS: In contrast to surgery, transcatheter closure of atrial septal defect preserves atrial and right ventricular function. Tissue Doppler derived strain rate can be applied to provide quantitative analysis of regional atrial and ventricular performance.

Adolescent↗
PubMed1993

Influence of left ventricular assist on valvular regurgitation.

BACKGROUND: The effects of mechanical left ventricular assist on the nonassisted right ventricle have not been fully elucidated. Current information indicates that the right ventricle benefits from a lower left atrial pressure; however, ventricular septal shifting and increased venous return caused by left ventricular assist impair right ventricular function. Acute intraoperative alterations in mitral and tricuspid valve regurgitation (MR and TR, respectively) may occur as a result of mechanical left ventricular assist but have not yet been documented. METHODS AND RESULTS: Eight patients undergoing implantation of a left ventricular assist device (LVAD) as a bridge to transplantation were studied during surgery by transesophageal echocardiography. MR was present in seven of eight patients, and TR was present in eight of eight patients before LVAD implant (mean MR jet area, 10.6 +/- 2.4 cm2, mean TR jet area, 4.8 +/- 1.0 cm2). Immediately after LVAD placement, MR was still present in seven of eight patients, and TR was present in eight of eight patients (mean MR jet area, 4.2 +/- 0.9 cm2; mean TR jet area, 8.4 +/- 1.9 cm2) (P < .05 preimplant versus postimplant jet area). These changes in MR and TR were associated with a decrease in left ventricular end-systolic dimension (62 +/- 4 versus 48 +/- 3 mm) and an increase in right ventricular end-systolic dimension (31 +/- 4 versus 40 +/- 5 mm) (P < .05 preimplant versus postimplant end-systolic dimension). No patients developed progressive right ventricular failure during 70 to 279 days of LVAD support. CONCLUSIONS: Mechanical left ventricular assist causes an acute decrease in preexisting MR. However, left ventricular assist may acutely worsen TR, presumably by shifting the ventricular septum leftward and increasing venous return to the right ventricle.

Cardiomyopathy, Dilated↗
PubMed2000

Fetal cardiovascular function during prolonged magnesium sulfate tocolysis.

The purpose of this study was to evaluate the fetal cardiovascular function during prolonged magnesium sulfate tocolysis. We performed a fetal ultrasonographic examination in 15 patients (Mg group) during magnesium sulfate tocolysis for the treatment of preterm labor. The maternal serum magnesium concentration was 5.7 +/- 0.5 mg/dl at the time of the examination. Sixteen fetuses in normal pregnancies at similar gestational ages were used as the control group. The fetal heart rate and the middle cerebral artery pulsatility index in the Mg group were lower than in the control group (p < 0.01). Fractional shortening (FS) of the right ventricle in the Mg group was lower (p < 0.01), while FS of the left ventricle was higher (p < 0.01) than in the controls. The calculated blood flow through the tricuspid orifice in the Mg group was lower than in the control group (p < 0.01). In contrast, the blood flow through the mitral orifice in the Mg group was higher than in the control group (p < 0.01). In conclusion, in spite of the fact that the right ventricular function is depressed, the fetus maintains its cardiac output during prolonged hypermagnesemia by increasing its left ventricular function. These results indicate the different fetal intracardiac and peripheral circulation, especially in the brain, from normal fetuses.

Adult↗
PubMed1994

Survival in primary pulmonary hypertension. Validation of a prognostic equation.

BACKGROUND: The prognosis of patients with primary pulmonary hypertension (PPH) remains a major problem for the planning and assessment of therapeutic interventions. The objectives of this study were (1) to characterize mortality in a Mexican population of patients with PPH and to investigate factors associated with survival and (2) to test the applicability in this population of the prognostic equation proposed by the US National Institutes of Health study on PPH. METHODS AND RESULTS: A dynamic cohort of patients with PPH at our institution were enrolled between June 1977 and August 1991 and prospectively followed at regular intervals through September 1992. Measurements at diagnosis included hemodynamic and pulmonary function variables in addition to information on demographic data and medical history. The response to vasodilator treatment was also analyzed. The estimated median survival of the group was 4.04 years (95% confidence interval, 2.98 to 5.08 years). Variables associated with poor survival (univariate analysis) included an elevated mean right atrial pressure, a decreased cardiac index, and a decreased mixed venous PO2. A reduced forced vital capacity and the absence of vasodilator treatment were also associated with poor survival. A multivariate Cox proportional-hazards regression analysis was used to assess the adjusted hazard ratios, hence the relative contributions of the variables controlling for confounding. Reduced forced vital capacity and cardiac index and increased right atrial pressure were still significantly associated as risk factors for survival in patients with PPH. Survival as computed by the equation correlated with real survival of PPH patients with positive predictive values of 87%, 91%, and 89% at 1, 2, and 3 years, respectively. The equation, however, was relatively unable to predict deaths in our population, in part because of the strict limits of poor prognosis. CONCLUSIONS: Mortality in PPH is largely associated with hemodynamic variables that assess right ventricular function. The proposed prognostic equation had a high sensitivity and a relatively low specificity to predict survival in our PPH population. To improve this specificity it may be necessary to increase the limits of poor prognosis as defined by the equation.

Adult↗
PubMed1988

Cardiac function in open-chest dogs after left to right ventricular shunting and right coronary artery occlusion.

Patients with acquired ventricular septal defect (VSD) after myocardial infarction have a particularly bad prognosis if right ventricular function is severely impaired. The significance of an ischaemic right ventricular free wall on cardiac function during interventricular shunting was examined in open-chest dogs. An external interventricular shunt could be opened and closed at will, and by occlusion of the right coronary artery (RCA), a part of the right ventricular free wall was rendered ischaemic. Aortic flow decreased by 8 +/- 2% when the shunt was opened in the presence of a normal right ventricle, and by 16 +/- 2% (difference: P less than 0.05) in the presence of right ventricular ischaemia. Aortic flow fell by 19 +/- 3% when the RCA was occluded. Right ventricular dyskinesia was demonstrated after occlusion of RCA, by recording segment lengths in the right ventricular free wall. The dyskinesia was aggravated when the shunt was opened. The left ventricle exerted a 'negative' work on the ischaemic right ventricular free wall. Retention of blood in the right ventricle, with a subsequent decline in left ventricular filling and an almost unchanged interventricular shunting of blood, explain why aortic flow fell more when the shunt was opened in the presence of right ventricular ischaemia.

Animals↗
PubMed1996

Pulmonary vasoconstriction due to impaired nitric oxide production after cardiopulmonary bypass.

BACKGROUND: Pulmonary hypertension is a serious complication after cardiopulmonary bypass (CPB). This study tests the hypothesis that CPB provokes oxidant-mediated pulmonary endothelial dysfunction, leading to reduced nitric oxide (NO) production and pulmonary vasoconstriction. METHODS: Twelve piglets underwent 2 hours of CPB. In 6 of them, CPB prime was supplemented with N-mercaptopropionylglycine and catalase, whereas the others were not treated. Left and right ventricular function were evaluated from end-systolic elastance and Starling analysis. Pulmonary vascular resistance and transpulmonary NO production (measuring NO2-, NO3-) were determined to assess pulmonary endothelial function. RESULTS: Cardiopulmonary bypass caused a significant increase in pulmonary vascular resistance (83 +/- 12 to 212 +/- 30 dynes.cm-5.s kg-1, p < 0.05), associated with a reduction of NO production (8.8 +/- 1.4 to 2.5 +/- 0.5 mumol/min, p < 0.05) and depressed right ventricular function (56 +/- 12% of control), whereas N-mercaptopropionylglycine and catalase added to the CPB allowed a substantial improvement of these deleterious effects of CPB. CONCLUSIONS: Cardiopulmonary bypass impairs pulmonary NO production, resulting in pulmonary vasoconstriction and right ventricular dysfunction, which can be reduced by antioxidants. These findings imply the validity of NO inhalation therapy for postoperative pulmonary hypertension as a supplementation of endogenous endothelium-derived relaxing factor.

Animals↗
PubMed1991

Left and right ventricular diastolic function during acute pericardial tamponade.

The aim of the study was to determine the effect of acute pericardial tamponade on left (LV) and right ventricular (RV) intracavitary and transmural pressure-volume (P-V) relations and to assess the effect of changing blood volume during tamponade on LV and RV volumes. The experiments were done in 11 acutely instrumented anaesthetized dogs in which LV and RV volumes were determined by computed tomography (CT) (n = 5) and LV and RV diameters by sonomicrometry (n = 6). Pressures were measured in the pericardium (balloon transducer), in the aorta and in the ventricles. Incremental pericardial infusion (up to 180 ml) caused a progressive left and upward shift of the LV and the RV intracavitary P-V relationship. This shift was entirely due to increased pericardial pressure (PP). The induction of tamponade caused no change in the LV and RV transmural P-V relationship. During tamponade with ventricular filling pressures above 10-15 mmHg, blood volume expansion caused only minimal increase in LV and RV volumes. In conclusion, pericardial tamponade shifted the LV and the RV intracavitary diastolic P-V relation by increasing PP. However, there was no change in the transmural P-V relationship, indicating unchanged myocardial compliance. Volume loading caused only minimal increase in LV and RV volumes during tamponade.

Animals↗