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The evaluation of right ventricular performance using krypton-81m.

The availability of krypton-81m suitable for intravenous injection provides an easy means for assessing right ventricular function. The superimposition of the other heart chambers does not constitute a problem. The activity in the left heart is negligible and the study can be performed in the right anterior oblique position to obtain optimal separation between the right atrium and the right ventricle. Lung activity is quite high and should be corrected before computing the right ventricular ejection fraction. This correction can be accomplished by performing Tc-99m MAA perfusion scintigraphy. The measurement of the right ventricular ejection fraction appears to be reproducible with very small inter-and intraobserver variability. Good quality phase and amplitude images can be obtained with such high count rates.

Cardiac Output↗

Biventricular function during postextrasystolic potentiation in man. A study using list-mode radionuclide ventriculography.

The effects of postextrasystolic potentiation during spontaneous ventricular ectopy on both left and right ventricular function were studied in 12 patients with the aid of list-mode radionuclide ventriculography. The left ventricular ejection fraction showed a significant increase (+ 11.0 +/- 5.0%; p less than .001) with associated mild increases in end-diastolic volumes (+ 4.9 +/- 4.6; p less than .01) and significant decreases in end-systolic volumes (-13.4% +/- 7.3%; p less than .001). A more heterogeneous response was seen for the right ventricle. Right ventricular ejection increased significantly in 8/12 patients (+ 3.3 +/- 3.0%; p less than .02). Despite a large increase in end-diastolic volumes (+ 10 +/- 7.9%; p less than .001), there were only mild changes in end-systolic volumes (+ 2.2 +/- 9.0; p = NS). It is concluded that, for spontaneous ventricular ectopy in man, the increase in right ventricular ejection fraction reflects improved ventricular filling whereas the increase in left ventricular ejection fraction is linked to improved emptying.

Adult↗

Gated right ventricular studies using krypton-81m: comparison with first-pass studies using gold-195m.

Krypton-81m, given by continuous i.v. infusion, has been successfully used for the equilibrium ECG-gated assessment of right ventricular function. We compared gated studies with 81mKr (half-life 13 sec) with first-pass studies using 195mAu (half-life 30.5 sec). Krypton studies analyzed using variable regions of interest (ROIs) led to a significantly higher calculated right ventricular ejection fraction (RVEF) than with a fixed ROI, both with and without background correction. The differences between first-pass studies and gated studies without background correction were significant (p less than 0.01), whereas they were not with background correction. These data suggest that large systematic errors exist in the calculation of RVEF depending on the analysis method and that background correction is important when different techniques are compared.

Adult↗

[Effect of tricuspid annuloplasty in mitral/aortic valve replacement on the clinical aspects and global function of the right heart chamber].

The clinical improvement after mitral or aortic valve surgery is primarily due to the correction of the aortic/mitral valve function and the subsequent decrease of pulmonary artery pressure. The hemodynamic effect of an additional tricuspid annuloplasty, however, is still unclear. To assess the influence of a tricuspid annuloplasty using DeVega- or Carpentier-technique on the clinical outcome, hemodynamics, and right ventricular function in patients with moderate to severe tricuspid insufficiency, 38 patients were studied pre- and 11 +/- 4 months postoperatively. The clinical degree of left heart failure was graded according to the criteria of the NYHA. The extent of right heart failure (RHF) was determined using a clinical score from 0 (no signs) to 3 (severe RHF with pleural effusion/ascites). Mean pulmonary artery pressure (PAPm), end-diastolic volume index (RVEDVI), and ejection fraction (RVEF) of the right ventricle using biplane cineventriculography, as well as the angiographic and dopplerechocardiographic degree of tricuspid insufficiency were determined. The patients were assigned to three groups: gr.I (n = 12): preoperatively no tricuspid insufficiency (TI), gr. II (n = 12): with preop. TI and without tricuspid annuloplasty (TA), gr. III (n = 14): with preop. TI and TA. The patients of all three groups improved postoperatively from NYHA functional class III to class II (p less than 0.001). The clinical score of RHF decreased from 0.8 +/- 0.5 to 0.3 +/- 0.5 in gr. I, from 1.4 +/- 1.1 to 0.6 +/- 0.7 in gr. II, and from 1.7 +/- 1.0 to 0.8 +/- 0.8 in gr. III (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗

Heart function and morphology in rats with chronic large myocardial infarction.

Large transmural myocardial infarctions were created in rats by occlusion of the descending branch of the left coronary artery. Four weeks after surgery, parameters of left and right ventricular function and of peripheral circulation were measured in the closed-chest, anesthetized animals and compared with those obtained in sham-operated controls. The morphology of the hearts was examined both at the macroscopic and cell size level. Cardiac output, LVSP, and the LV weight/body weight ratio were markedly lower than in sham-operated controls. LVEDP was elevated up to 32 +/- 2 mm Hg. On the other hand, RVSP, RV dp/dtmax, the right ventricular weight/body weight ratio, and the volume of myocytes isolated from the right ventricular free wall were increased. Histological examination of the lungs revealed marked thickening of the tunica media of small pulmonary arteries with narrowing of the lumen. These changes are considered to represent the morpohological basis for the increased pulmonary vascular resistance which was associated with right ventricular pressure overload and hypertrophy.

Animals↗

Assessment of right ventricular diastolic and systolic function in patients with dilated cardiomyopathy using cine magnetic resonance imaging.

Cine magnetic resonance imaging (MRI) can provide clear endocardial margins of the entire right ventricle, and Simpson's algorithm can be applied to obtain the volumes at multiple phases of the cardiac cycle. Time-volume curves of the right ventricle were obtained by using cine MRI in 10 patients with dilated cardiomyopathy (DCM) and eight normal volunteers to assess right ventricular function. There were no significant differences in volumes and ejection fraction of the right ventricle between the group with DCM and the normal group. In the group with DCM the time to peak filling rate was increased (p less than 0.05) and the filling fraction was decreased (p less than 0.01). In the patients with DCM cine MRI demonstrated normal volumes and ejection fraction of the right ventricle in contradistinction to the marked increase in volumes and the decrease in ejection fraction of the left ventricle; with the use of time-volume curves of the right ventricle, impairment of diastolic function of the right ventricle was demonstrated.

Adult↗

Tissue Doppler velocities of the right and left ventricles and their association with C-reactive protein and homocysteine levels in Behcet's disease.

In the present study, we aimed to investigate whether tissue Doppler imaging could provide more information than standard echocardiography about left and right ventricular functions and their relations to homocysteine and C-reactive protein (CRP) levels in the course of Behcet's disease (BD). In the right ventricle, patients with BD had lower early diastolic tricuspid annular velocity and early diastolic/late diastolic tricuspid annular velocity ratios than the control group. Mitral and tricuspid annular systolic velocities did not significantly differ; however, diastolic velocities were correlated with duration of the disease. In addition, early/late diastolic mitral annular velocity ratio and early/late diastolic tricuspid annular velocity ratios showed an inverse relation with ocular involvement, serum homocysteine, and CRP levels in patients with BD.

Adult↗

Diagnosis of pericardial effusion and its effects on ventricular function using gated Tc-99m sestamibi perfusion SPECT.

Pericardial effusion is a common disorder associated with a variety of medical disorders. Diagnostic methods of choice include echocardiography, CT, and MRI. However, diagnosing pericardial effusion with radionuclides is uncommon. A pericardial effusion under pressure may result in tamponade and hemodynamic compromise, which constitutes a cardiac emergency, necessitating emergency intervention with pericardiocentesis or pericardiotomy. Presented is an unusual case of a patient who was referred to the nuclear cardiology laboratory for evaluation of atypical chest pain using stress and rest Tc-99m sestamibi perfusion SPECT. The patient had a large pericardial effusion evident on planar projection images and tomograms. From the gated perfusion study, the authors were able to evaluate left and right ventricular function and to exclude cardiac tamponade because there was no evidence of diastolic collapse of the right ventricle.

Aged↗

Right atrial ischemia exacerbates hemodynamic compromise associated with experimental right ventricular dysfunction.

To determine the importance of right atrial function with acute right ventricular dysfunction, sequential right ventricular and right atrial ischemia were induced in 15 dogs. Right ventricular ischemia resulted in right ventricular free wall dyskinesia, right ventricular dilation by ultrasound, elevated right ventricular filling pressure and paradoxic septal motion. There were decrements in right ventricular systolic pressure (28.9 +/- 5.5 to 25.5 +/- 4.6 mm Hg) (p less than 0.05 for these and all subsequent values) and stroke work (5.66 +/- 0.94 to 2.66 +/- 0.62 g.m/m2), resulting in reductions in left ventricular preload, systolic pressure (123 +/- 11 to 97 +/- 12 mm Hg) and stroke volume (24.2 +/- 4.3 to 19.1 +/- 5.2 ml). Right atrial contractility was augmented, as indicated by increases in peak A wave amplitude (ratio of peak A wave to mean right atrial pressure 1.22 +/- 0.02 to 1.46 +/- 0.3) and right atrial stroke work (0.11 +/- 0.02 to 0.25 +/- 0.05 g.m/m2). Right atrial ischemia depressed right atrial contraction, as indicated by decreased A wave amplitude (ratio of peak A wave to mean right atrial pressure 1.46 +/- 0.3 to 1.04 +/- 0.2) and stroke work (0.25 +/- 0.05 to 0.04 +/- 0.01 g.m/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

[Current role of radionuclide imaging in pediatric cardiology].

Three main nuclear medicine methods are used in paediatric cardiology: sequential first-pass radionuclide imaging of the cardiac cavities, radionuclide equilibrium ventriculography and radionuclide myocardial imaging. Valuable functional information is obtained, and invasive explorations can be avoided in an ever increasing number of cases. Of particular interest is left-to-right shunt measurement which indicates that atrial septal defects must be surgically corrected when the pulmonary/systemic flows ratio (QP/QS) is above 2. This technique is also useful to evaluate the tightness of repairs in ventricular and atrial septal defects. Radionuclide studies of the right and left ventricles may detect dysfunction in one or the other cavity. The left ventricular ejection fraction is reduced in myocardiopathy an in aortic or mitral valve diseases seen at a late stage. The right ventricular function is often abnormal, notably during exercise, after repair of the tetralogy of Fallot and after atrial correction of complete transposition of the great arteries. An altered ejection fraction in patients with single ventricle is also a sign of deterioration. Right ventricular diastolic overload evaluated by radionuclide equilibrium ventriculography correlates with the QP/QS ratio value in atrial septal defects and with the inducibility of ventricular tachycardia by endocavitary pacing in repaired tetralogy of Fallot. Thallium 201 myocardial imaging provides information on myocardial ischaemia, notably that associated with congenital abnormalities of the coronary arteries. Its use had now been extended, albeit with some limitations, to the evaluation of right ventricular systolic overload. Other radionuclide techniques are being developed with new tracers: Kryton 81m for studies of the right ventricle, short-lived radionuclides for first-pass studies, Iodine 123-labelled fatty acids for myocardial imaging. More recently, some substrates, such as deoxyglucose, have been labelled with positron emitters permitting in vivo metabolic studies.

Cardiac Output↗

Inhaled nitric oxide versus prostacyclin in chronic shunt-induced pulmonary hypertension.

OBJECTIVE: Cardiac surgery for congenital heart defects is commonly complicated by shunt-induced chronic pulmonary hypertension and associated acute hypertensive crises. To investigate the effects of vasodilators in chronic and acute pulmonary hypertension, we used the innominate artery to create a growing aortopulmonary shunt in young piglets. METHODS: Pulmonary hemodynamics and right ventricular function and their responses to hypoxia, intravenous prostacyclin, and inhaled nitric oxide were investigated after closure of the shunt by using pulmonary flow-pressure relationships, pulmonary vascular resistance partitioning, pulmonary vascular impedance, and ventriculoarterial coupling expressed as the ratio of right ventricular end-systolic elastance to effective pulmonary arterial elastance. RESULTS: Shunt-induced pulmonary hypertension was associated with medial hypertrophy of pulmonary arteries, increased resistance, increased elastance, increased wave reflection, and preserved ventriculoarterial coupling. Hypoxic pulmonary vasoconstriction was blunted in the shunt group. Compared with prostacyclin, inhaled nitric oxide was a more effective vasodilator in the shunt group and in hypoxia. Effective pulmonary arterial elastance and right ventricular end-systolic elastance increased in chronic (shunt) and acute (hypoxic) hypertension and decreased with vasodilators, preserving a normal coupling. CONCLUSIONS: A growing aortopulmonary shunt in the young pig is a reliable model of chronic pulmonary hypertension, with medial hypertrophy, increased resistance, and increased elastance. In this model inhaled nitric oxide is a better pulmonary vasodilator than intravenous prostacyclin, with neither drug having a specific inotropic effect, and normal coupling is preserved in chronic and acute pulmonary hypertension.

Administration, Inhalation↗

[Studies on alteration in biventricular dimensions during stepped elevation in pulmonary arterial pressure with special reference to right ventricular bellows action].

A new method for inserting ultrasonic crystals into the interventricular septum (IVS) of dogs was performed to measure the right and left ventricular septum-to-free wall dimensions (RVD, LVD) in a line. The advantage of this technique is minimal damage of the pericardium and no damage of the ventricular wall. The segmental lengths in the right and left ventricles (RVSL, LVSL) were also measured. Stepped elevation of pulmonary arterial pressure induced by ligation of pulmonary arterial branches caused an increase in RVD and a decrease in LVD. IVS shifted to the left and transseptal pressure gradient was reduced. RVD and RVSL increased and percent shortening in RVD and RVSL during ejection decreased with pulmonary hypertension. Although the change in RVD and RVSL basically related each other, those changes in RVD was more evident than in RVSL. Thus, the measurement of RVD and RVSL is indispensable for investigating the right ventricular function. There was a high correlation between the stroke volume and the shortening in RVD (expressed as percent of the control value, respectively) during ejection in pulmonary hypertension (F = 13.88 greater than F 1(20)(0.005) = 9.94), therefore we speculate that right ventricular bellows action is essential in blood ejection from the right ventricle. Furthermore the stroke volume decreased as the shortening in RVSL during ejection decreased (F = 3.17 greater than F 1(20)(0.1) = 2.97), therefore shortening in RVSL is thought to be an important factor causing bellows action, however further investigation is necessary.

Animals↗

Measurement of right ventricular volumes from ECG-gated steady-state krypton-81m angiocardiography.

The physical characteristics of krypton-81m makes it particularly suited for the study of right ventricular function, but its ultrashort half-life (13.3 s) precludes in vitro measurements of blood pool specific activity needed for count based determination of ventricular volumes. A combined geometric count based method was developed to measure absolute right ventricular volumes during steady state krypton-81m angiocardiography: background corrected ventricular count rates were converted to volumes using a count to volume calibration factor calculated in an 'internal reference ROI' located in the right ventricular outflow tract. Stroke volumes calculated with this method were shown to be comparable to thermodilution determined stroke volumes and the ability of the method to monitor changes in right ventricular volumes was demonstrated during intervention studies.

Angiocardiography↗

[Total correction of complete transposition of the great arteries (d-TGA) and Fontan procedure for tricuspid atresia(TA)].

Since 1975, 87 patients underwent total correction consisting of 35 cases of Mustard procedure with 6 early deaths (17.1%), 36 Senning with 2 deaths (5.6%), 12 Rastelli operations with 4 deaths (33.3%), and Jatene procedure on 4 cases without mortality. Sixteen patients out of 63 early survivors following intraatrial repair resulted in fatal outcome. In 17 with a modified senning procedure with a pedicled autologous pericardial patch on the functional left atrium, 8 died of pulmonary venous obstruction caused by thickening and calcification of pericardium. However, no death was seen in 17 patients with original Senning procedure. Right ventricular function remained poor in cases with intra-arterial repair and accounted for relatively poor long-term results. Although Rastelli operation carried high early mortality, late death was seen only in 1. Jatene procedure was performed in 4 ranging in ages from 5 months to 6 years without mortality. Fontan procedure was done on 22 patients with 2 early deaths and no late death in tricuspid atresia. Average cardiac index after surgery was 2.6 +/- 0.6. Cardiac index showed close correlation with preoperative cross sectional area of both pulmonary artery divided by body surface area (PA-index), but had poor correlation with right atrial pressure or left ventricular volume.

Age Factors↗

Sildenafil citrate for the treatment of patients with cardiovascular diseases with exclusion of coronary artery disease and hypertrophic subaortic stenosis. Its beneficial effect on patients chronic Chagas's and diabetic cardioneuromyopathies, hypertensive and hypertrophic cardiomyopathies, with or without chronic congestive heart failure.

UNLABELLED: Sildenafil citrate is a potent donor of nitric oxide that has been proved to be effective for the treatment of male erectile dysfunction, but it has been contraindicated in patients with cardiovascular diseases, because of sudden death occurred to some of them. Based on the known vasodilator effect of nitrix oxide, effect that should be beneficial for some cardiomyopathies, this work was carried out in order to prove the cardiovascular effects of sildenafil citrate on: 1) heart rate, rhythm and repolarization changes on the ecg; 2) systolic and diastolic arterial blood pressure; 3) left ventricular systolic function and 4) right and left ventricular diastolic function in 26 patients suffering from the following cardiomyopathies: chronic Chagas's and diabetic cardioneuromyopathies, hypertensive and/or hypertrophic cardiomyopathies with or without chronic congestive heart failure. RESULTS: sildenafil citrate 50 mgr after a single oral dose: 1) improved the ecg findings in some patients, worsening the basal ecg in none of the studied patients; 2) significantly reduced systolic and diastolic arterial blood pressure being such reduction very strong in those with basal high level 3) significantly improved left ventricular systolic function in those patients with basal reduced function and 4) Right ventricular diastolic function evaluation: Sildenafil citrate 50 mgr significantly modified to normal pattern the E/A basal altered ratio in those patients with the inverted pattern as well as in those with restrictive pattern of tricupid diastolic influx to the right ventricle during the echo-duplex interrogation (p < 0.0001) 5) Left ventricular diastolic function evaluation: Sildenafil citrate 50 mgr significantly modified to normal pattern the E/A basal altered ratio in those patients with the inverted pattern as well as in those with restrictive pattern of mitral diastolic influx to the left ventricle, during the echo-duplex interrogation (p 0 <.0001). CONCLUSIONS: Based on the above findings it is feasible to propose the use of sildenafil citrate to treat patients with cardiovascular diseases, with exclusion of severe obstructive coronary artery disease, hypertrophic subaortic stenosis and patients with funduscopic alterations that may be affected by a significant and acute increase of flow within the ophthalmic arteries. The right ventricular diastolic changes observed with Sildenafil Citrate may be useful in patients with abnormal right ventricular compliance such as pulmonary stenosis or hypertension.

Blood Pressure↗

[Function of the heart chambers in acute myocardial infarct].

A study of 87 patients, admitted to hospital within the first day of acute myocardial infarction (AMI) identified 3 groups of patients on the basis of their pulmonary capillary occlusion pressure (OP) values. Sixteen normal subjects made up the control group. Myocardial contractility and volume characteristics obtained by sectoral scanning were reviewed. It was demonstrated that the contractility of the left and right heart chambers had different patterns of change in relation to the magnitude of pressure: left-atrial and right-ventricular ejection fraction (EF) gradually declined, and normal pressure values were associated with right-ventricular hyperfunction. Right-ventricular EF also decreased as the OP grew, yet it did not reach the critical values as observed with the left-ventricular EF. The predominance of the right-ventricular function over the left-ventricular one might be one of the mechanisms underlying the development of insufficiency in the lesser circulation. Contractility unbalance was also shown to exist between the right and left atria. A rise in the end systolic volume in the presence of unchanged end diastolic volume is the earliest manifestation of reduced left-ventricular contractility in acute myocardial infarction.

Cardiac Volume↗

Functional and metabolic recovery of the right ventricle during Bosentan therapy in idiopathic pulmonary arterial hypertension.

An impaired high-energy phosphate metabolism might play a critical role in the pathogenesis of right ventricular (RV) failure due to chronic pulmonary arterial hypertension (PAH). 31P-NMR spectroscopy is well established for measurements of high-energy phosphate metabolites in various left ventricular heart diseases, however, mainly for technical and sensitivity reasons, its successful transfer for measurements in the RV is currently missing. In the present study, the usefulness of this non-invasive approach is not only shown in RV failure due to PAH but also tested during subsequent therapy.

Antihypertensive Agents↗

Haemodynamic requirements for an ideal pulmonary vasodilator.

An ideal vasodilator should be selective for the pulmonary vascular bed, thus minimizing side-effects from reduced systemic resistance. It must achieve not only a drop in pulmonary vascular resistance but also a marked decrease in pulmonary arterial pressure. The ideal drug should increase cardiac output and pulmonary venous oxygen saturation. An increase in oxygen delivery to the peripheral tissues should be achieved at a lower right ventricular afterload both at rest and during exercise. Right ventricular function should be improved. The effects of vasodilator therapy should be so marked that it should be possible to follow them non-invasively by radionuclide methods and exercise tolerance tests. The aim of vasodilator therapy is a regression of pulmonary hypertension and of right ventricular hypertrophy, an improved quality of life, and above all a longer survival.

Blood Pressure↗