Feasibility study of a mixed reality tool for real 3D visualization and planning of left atrial appendage occlusion.

In left atrial appendage occlusion (LAAO), pre-procedural imaging is pivotal to describe the highly variable LAA anatomy and to guide the operator in device sizing and interventional planning. Multiplanar reconstruction and 3D rendering are used for the interpretation of 3D CT datasets. However, this method of review of such imaging, which is mediated by 2D screens, may be limited due to the lack of true 3D visualization of the structures of interest; Mixed Reality (MxR) may further improve the CT-based pre-procedural planning by allowing for real-3D visualizations with holographic replicas of anatomical models. In this manuscript we present a novel software based on MxR and we evaluated its feasibility on different LAA morphologies. The morphological analysis of the holographic anatomical models was successfully applied for all the patients (n â€‹= â€‹4) independently from the morphology and it was performed in less than 10 minutes. Our findings suggest that with further developments MxR could have the potential to become a pivotal tool in LAA occlusion planning thanks to the real-3D perception, possibly leading to a more accurate and faster planning phase.

A statistical shape model of the left ventricle from real-time 3D echocardiography and its application to myocardial segmentation of cardiac magnetic resonance images.

OBJECT: We present in this paper the application of a statistical shape model of the left ventricle (LV) built from transthoracic real time 3D echocardiography (3DE) to segment the LV endocardium and epicardium in cardiac magnetic resonance (CMR) images. MATERIAL AND METHODS: The LV model was built from a training database constituted by over 9000 surfaces obtained from retrospectively selected 3DE examination of 435 patients with various pathologies. Three-dimensional segmentation of the endocardium and the epicardium was obtained by processing CMR images acquired in 30 patients with a dedicated active shape modelling (ASM) algorithm using the proposed LV model. RESULTS: The segmentation results obtained with the proposed method were compared with those obtained by the manual reference technique; similarity was proven by computing: i) point to surface distance (<2 mm), ii) Dice similarity coefficient (>89%), iii) Hausdorff distance (∼5 mm). This was furthermore confirmed by equivalence testing, linear regression and Bland Altman analysis applied on derived clinical parameters, such as LV volumes and mass. CONCLUSIONS: This study showed the potential usefulness of the proposed inter-modal ASM approach featuring a 3DE-based LV model for the 3D segmentation of the LV myocardium in CMR images.

P594Contrast transthoracic echocardiography as a gatekeeper for patent foramen ovale closure.

BACKGROUND.: The presence of patent foramen ovale (PFO) has been linked to many illness, including cryptogenic stroke, transient ischemic attack, migraine, platypnea-orthodeoxia syndrome and decompression sickness in scuba divers. Transesophageal echocardiography is the gold standard technique for the visualization of atrial septal anatomy, but it is a secondary level exam, not always available, with additional associated costs and not completely free from procedural risks. Standard transthoracic echocardiography (TTE) has a too low sensitivity for PFO screening. PURPOSE.: The aim of the study was to assess the role of TTE associated with agitated saline contrast injection (contrast-TTE) as a gatekeeper for the identification of PFO in a large cohort of patients undergoing selection for percutaneous closure. METHODS.: A total of 200 patients undergoing a diagnostic work-up for the identification of PFO was imaged by contrast-TTE at rest and after provocative maneuvers (PM: Valsalva in all cases). Contrast TTE was graded from 0 to 4 on the bases of bubbles counting (0: no bubbles; 1: < 10 bubbles; 2: 10-30 bubbles; 3: >30 bubbles; 4: complete LV opacification). PFO closure was performed after a consensual clinical decision by the cardiologist and the neurologist taking into account comprehensive imaging, clinical evaluation and thrombophilia screening. PFO closure was always monitored by intracardiac echocardiography. RESULTS.: At baseline contrast TTE was positive (≥2) in 34 patients (17%) while contrast TTE with PM was positive in 94 cases (47%). 27 out of 200 patients (14%) had an interatrial septal aneurysms. PFO closure was performed in 34 cases (17%). All of these had severe right-to-left shunting (≥3) at contrast TTE and 9 cases had also an interatrial septal aneurysms. The procedure was aborted in only 1 patient due to a complex defect anatomy. CONCLUSION.: Contrast TTE with PM may be not only considered an accurate tool for the detection of PFO but may be also inserted in the diagnostic work- up as a primary gatekeeper for percutaneous closure. Severe shunting at contrast TTE influences final decision making in a large cohort of cases undergoing screening for PFO closure.

Production and characterization of monodisperse plutonium, uranium, and mixed uranium-plutonium particles for nuclear safeguard applications.

In order to prevent nuclear proliferation, the isotopic analysis of uranium and plutonium microparticles has strengthened the means in international safeguards for detecting undeclared nuclear activities. In order to ensure accuracy and precision in the analytical methodologies used, the instrumental techniques need to be calibrated. The objective of this study was to produce and characterize particles consisting of U, Pu, and mixed U-Pu, suitable for such reliability verifications. A TSI vibrating orifice aerosol generator in connection with a furnace system was used to produce micrometer sized, monodispersed particles from reference U and Pu materials in solution. The particle masses (in the range of 3-6 pg) and sizes (approximately 1.5 microm) were controlled by the experimental conditions and the parameters for the aerosol generator. Size distributions were obtained from scanning electron microscopy, and energy-dispersive X-ray analysis confirmed that the particle composition agreed with the starting material used. A secondary ion mass spectrometer (SIMS) was used to characterize the isotopic composition of the particles. Isobaric and polyatomic interference in the SIMS spectra was identified. In order to obtain accurate estimates of the interference, a batch of Pu particles were produced of mainly (242)Pu. These were used for SIMS analysis to characterize the relative ionization of Pu and U hydride ions and to determine the SIMS useful yields of U and Pu. It was found that U had a higher propensity to form the hydride than Pu. Useful yields were determined at a mass resolution of 450 for U-Pu particles: (1.71 +/- 0.15) % for Pu and (0.72 +/- 0.06) % for U. For Pu particles: (1.65 +/- 0.14) % for Pu. This gave a relative sensitivity factor between U and Pu (RSF(U:Pu)) of 2.4 +/- 0.2. However, the RSF(U:Pu) showed large fluctuations during the sputtering time for each analyses of the mixed U-Pu particles, in the range of 1.9-3.4.

Usefulness of transoesophageal echocardiography before cardioversion in patients with atrial fibrillation and different anticoagulant regimens.

OBJECTIVES: To evaluate the prevalence of atrial thrombi in patients with atrial fibrillation undergoing different anticoagulation regimens before cardioversion; to evaluate the usefulness of transoesophageal echocardiography (TOE) guided cardioversion to prevent thromboembolic complications; and to correlate the presence of atrial thrombi with clinical and echocardiographic data. METHODS: 757 consecutive patients admitted as candidates for cardioversion of atrial fibrillation were enrolled in the study. They were divided into four groups: effective conventional oral anticoagulation, short term anticoagulation, ineffective oral anticoagulation or subtherapeutic anticoagulation, and effective oral anticoagulation with a duration of < 3 weeks for various clinical reasons. All patients underwent TOE before cardioversion; in the presence of atrial thrombi or extreme left atrial echo contrast, cardioversion was postponed. The incidence of thromboembolic events was evaluated after cardioversion. RESULTS: Atrial thrombi were detected in 48 of the 757 (6.3%) patients. No significant differences in the percentage of atrial thrombosis were found in the four study groups. Patients with atrial thrombosis were older and had a higher percentage of mitral prosthetic valves, lower left ventricular ejection fraction, more severe atrial spontaneous echo contrast, and lower Doppler left atrial appendage velocities. 648 patients were scheduled for cardioversion. Cardioversion was successful in 89% of patients without any major thromboembolic event. CONCLUSIONS: The prevalence of atrial thrombosis before cardioversion despite different treatments with anticoagulants is about 7% and a TOE guided approach may prevent the risk of embolic events.

Oxygen isotopic measurements by secondary ion mass spectrometry in uranium oxide microparticles: a nuclear forensic diagnostic.

To exploit oxygen isotopic measurement by SIMS as a diagnostic tool in nuclear forensics, the magnitude and reproducibility of 0-isotope instrumental mass discrimination for O-isotope standards in the SIMS laboratory at the Institute for Transuranium Elements has been evaluated. Tests for matrix-dependent discrimination effects on three different O-isotope standards with substantially different matrix compositions have been performed. The results were checked by an interlaboratory comparison of O-isotope discrimination with those obtained in the SIMS laboratory at the Lawrence Livermore National Laboratory on two standards. The results from the two laboratories are in very good agreement, indicating statistically indistinguishable instrumental mass discrimination factors for 180/160 ratios on the Cameca 6f and 3f, when the analyses are performed under the experimental conditions described. The 2sigma(mean) uncertainties of these factors are in the range of 0.3-0.9%. In accordance with the tested methodology, 0-isotope compositions were measured in three particulate uranium oxide samples of nuclear forensics interest.

Lowering of blood pressure and coronary blood flow in isolated systolic hypertension.

BACKGROUND: In essential hypertension, the lower limit of autoregulation of coronary flow shifts to higher perfusion and the hypertensive ventricle is at a higher than normal risk of ischemia, and less able to tolerate acute reduction of coronary perfusion pressure. Little is known about pattern of coronary flow in isolated systolic hypertension, a pathologic condition in which the elevated systolic blood pressure is associated with a lower than normal vascular compliance and normal or slightly greater than normal mean arterial pressure and vascular resistance. OBJECTIVE: To evaluate the effects of rapid normalization of blood pressure on coronary blood flow in isolated systolic hypertension. METHODS: We subjected 20 patients with isolated systolic hypertension to intraoperative hemodynamic and transesophageal echocardiographic monitoring during peripheral vascular surgery. Coronary flow velocity integrals and diameters in the left anterior descending coronary artery were evaluated under baseline conditions and after normalization of blood pressure, which occurred spontaneously during anesthesia (10 cases; group 1A) or was induced by infusion of nitrate (10 cases, group 1B). RESULTS: After normalization of systolic blood pressure integrals decreased significantly only for patients in group 1A; percentage changes of diameter were significantly greater for patients in group 1B. Therefore, coronary blood flow after normalization of systolic blood pressure increased for patients in group 1B (by 28+/-25%) and decreased for patients in group 1A (by 30+/-21%). Changes in integrals were inversely related to those in diameter (r= -0.72, P < 0.001); for patients in group 1A changes in coronary perfusion pressure and diameter were related to those of integrals (r= 0.94; P < 0.0005). CONCLUSIONS: In isolated systolic hypertension, despite there being similar changes of the systolic blood pressure, administration of nitrates caused a marked increase of coronary flow through direct effects on coronary circulation, whereas spontaneous normotension was associated with a significant reduction of coronary flow.

Analytical methods for thorium determination: a journey from conventional methods to novel applications.

Thorium may be determined using a variety of analytical methods. These may be based on chemical or physical principles or may make use of the radioactive decay of the individual thorium isotopes. The method to be used for a certain analytical purpose is selected as a function of the matrix of the sample and of the concentration of thorium. The present paper describes different methodologies, their range of application and discusses selected results. The methods described cover a concentration range of more than twelve orders of magnitude, i.e. from concentrated solutions to micrometre-sized particles. Emphasis is given to active radiometric techniques, chemical and instrumental analysis.

[Echo-Doppler study of the right ventricle in patients with chronic cardiac failure]. / Studio eco-Doppler del ventricolo destro nel paziente con scompenso cardiaco cronico.

Echocardiography is a well-established and accurate method for the evaluation of cardiac anatomy and function in patients with heart failure. In this review we summarize the role of echocardiography not only in assessing right ventricular anatomy and function, but also in the prediction of prognosis and in the study of ventricular interaction.

Diastolic ventricular interaction in normal and dilated heart during head-up tilting.

BACKGROUND: The normal human heart behaves as a single functional unit during preload reduction; adaptations of the left ventricle to head-up tilting is mediated through ventricular interdependence and biventricular-lung interaction. HYPOTHESIS: We hypothesized that reduction of venous return in dilated cardiomyopathy is likely to have a great effect on ventricular chamber geometry and filling. The aim of this study was to evaluate the effects of gradual head-up tilting in normal subjects and in patients with dilated cardiomyopathy, addressing special attention to right (RV) and left ventricular (LV) dimensions, geometry, and filling, and to biventricular-lung interaction. METHODS: Twenty normal subjects and 23 patients with moderate heart failure due to dilated cardiomyopathy were studied with two-dimensional and Doppler echocardiography in supine position and after 20 degrees, 40 degrees, and 60 degrees tilting. Right ventricular and LV dimensions, LV geometry, and tricuspid, mitral, and pulmonary venous flow patterns were recorded at each step of the study. Geometric changes of the LV were evaluated by measurements of volumes and diameters in the apical four-chamber view (which identifies the interventricular septum and lateral wall) and apical two-chamber view (which identifies the inferior and anterior wall of the LV). RESULTS: In the two groups, tilting was associated with reduction of RV area and LV diameter and volumes; percent variations in LV diameter and volumes recorded in four-chamber view were lower at each step of tilting than with those derived from the two-chamber view in controls and in patients. In normal subjects, mitral and tricuspid peak early flow velocities were decreased at any tilting level; peak late velocities were unchanged; peak velocity of systolic forward flow of the pulmonary vein was reduced, diastolic forward flow was unchanged, and the difference in duration between reverse pulmonary flow and forward mitral A wave was reduced. Doppler findings were qualitatively similar in patients, but tilting induced a more marked redistribution of LV filling to late diastole because of a significant increase in atrial contribution. CONCLUSIONS: Preload reduction by tilting induces profound effects on left and right dimensions, geometry, and filling in normal and dilated heart; reduction or RV dimensions are associated with changes in LV ventricular geometry (minimal reduction in septal-lateral diameter, marked reduction in anterior-posterior diameter), redistribution of right and left diastolic filling to late diastole, and redistribution of pulmonary venous flow to early diastole. These mechanisms are probably due to a favorable interaction between heart and lungs, which increases compliance within the pericardial space and facilitates redistribution of flow from the lungs. Even a minimal amount of preload reduction causes more marked effects in LV filling patterns in dilated cardiomyopathy than in normal hearts, confirming that ventricular interaction and pericardial constraint are increased when heart volume enlarges.

Exercise echocardiography versus exercise electrocardiography in the diagnosis of coronary artery disease in hypertension.

In hypertension, coronary artery disease (CAD) can be overestimated by stress electrocardiography (ECG) and scintigraphy due to frequent false-positive results. Exercise tests are also limited by an excessive blood pressure increase, and pharmacologic pressure normalization decreases the accuracy of the test. The aim of this study was to assess the accuracy of exercise echocardiography as an alternative test for CAD detection in hypertension, both before and after adequate blood pressure control. We studied 59 hypertensive and 59 normotensive patients undergoing coronary angiography for chest pain. Upright bicycle exercise ECG and echocardiographic tests were performed in each group in the absence of therapy; in hypertensives, the tests were repeated a day apart after blood pressure normalization with sublingual nifedipine. Significant CAD (lumen narrowing >50%) was detected in 22 hypertensive and 41 normotensive patients. In the two groups, sensitivity, specificity, and diagnostic accuracy of exercise echocardiography performed before treatment were not statistically different (95%, 94%, 94% in hypertensives and 82%, 77%, 83% in normotensives, respectively), but were significantly higher than for the exercise ECG test (68%, 70%, and 69%, respectively). After blood pressure lowering, exercise echocardiography sensitivity slightly decreased (91%), whereas specificity (100%) and diagnostic accuracy (96%) did not vary; on the contrary, exercise ECG sensitivity decreased to 45%. Therefore, according to our data, exercise echocardiography can be an accurate test and more reliable than exercise ECG to detect CAD in normotensives as well as in hypertensives. Normalization of blood pressure with nifedipine does not affect its accuracy, but markedly reduces the sensitivity of exercise ECG.

How the left and right sides of the heart, as well as pulmonary venous drainage, adapt to an increasing degree of head-up tilting in hypertrophic cardiomyopathy: differences from the normal heart.

OBJECTIVES: We aimed to assess the differences in the adaptive response of patients with hypertrophic cardiomyopathy (HCM) compared with normal subjects, as well as any association with increased susceptibility to the test. BACKGROUND: Diastolic function contributes importantly in the adaptation of the normal heart to head-up tilting. This mechanism may be disturbed by an impaired relaxation in HCM. METHODS: Twenty-one male patients with HCM (46 +/- 6 years old) and 22 healthy men (44 +/- 8 years) were studied using Doppler echocardiography after 1 and 10 min of head-up tilting at 20 degrees, 40 degrees and 60 degrees. RESULTS: In control subjects, tilting was associated with 1) a predominance of diastolic pulmonary venous flow and early left ventricular (LV) filling (atrium functioning as an open conduit); 2) right ventricular (RV) shrinkage; and 3) no LV dimensional variations. In patients with HCM, tilting was associated with 1) a prevalence of systolic pulmonary venous flow (atrium functioning as a reservoir in which filling depends on atrial relaxation and compliance) and late diastolic transmitral flow (atrium working as a booster pump); 2) LV shrinkage; and 3) no RV dimension variations. These mechanisms did not prevent stroke volume (SV) from decreasing at 40 degrees and 60 degrees in both groups. Because of a lower increase in heart rate (HR), a reduction in cardiac output (CO) was greater in patients with HCM. The responses were similar after 1 and 10 min of tilting in control subjects, whereas in patients, blood pressure (BP), SV and LV dimension fell more after 10 min. CONCLUSIONS: Adaptation of the normal heart to tilting is based on a ventricular interaction and LV diastolic properties; HCM relies on left atrial diastolic and systolic functions. An inadequate HR reaction to a fall in BP and SV in HCM (depressed reflexogenic activity) contributes to making CO more vulnerable by greater and more prolonged displacements.

Rapid diagnosis and management of thoracic aortic dissection and intramural haematoma: a prospective study of advantages of multiplane vs. biplane transoesophageal echocardiography.

AIMS: The purposes of this study were to compare the accuracy of multiplane vs. biplane transoesophageal echocardiography (TEE) in the diagnosis of aortic dissection and aortic intramural haematoma, and to test whether these techniques provide all the diagnostic information required to make management decisions. METHODS AND RESULTS: Fifty-eight consecutive patients with clinically suspected aortic dissection were studied with multiplane TEE; all cases who required surgery underwent intraoperative monitoring with multiplane TEE. The following multiplane TEE data were analysed: the angle between current and 0 degrees plane at which each view was obtained; the success rate in the evaluation of true and false lumen, entry tear, coronary artery involvement, aortic regurgitation, pericardial effusion. Advantages of multiplane over biplane TEE have been evaluated by the demonstration of usefulness of views obtained in planes other than 0 degrees-20 degrees or 70 degrees-110 degrees, assuming that with manipulation of a biplane probe a 20 degrees arc could be added to the conventional horizontal and vertical planes. On the basis of TEE findings, aortic dissection was confirmed in 36 cases (18 type A, 12 type B, six intramural haematoma). The specificity and sensitivity of TEE in terms of the presence or absence of aortic dissection or intramural haematoma were 100%. An additional clinical value of multiplane over biplane TEE in the evaluation of ascending aorta, aortic arch, entry tears and coronary artery involvement was demonstrated. All cases with type A aortic dissection or intramural haematoma involving the ascending aorta had an operation that was performed immediately after the diagnosis (hospital mortality, 13%). Patients with type B aortic dissection were treated medically; 25% of these cases were operated later (hospital mortality, 0%). CONCLUSIONS: Multiplane and biplane TEE have excellent and similar accuracies in the evaluation of aortic dissection and intramural haematoma. Multiplane TEE improves the visualization of coronary arteries, aortic arch and entry tears; it appears to be an ideal method as the sole diagnostic approach before surgery in type A aortic dissection.

Changes in pulmonary venous return during head-up tilting in man.

1. In a supine position, the heart fills to close to the limits of pericardial constraint and the pericardium may act to redistribute central blood volume from the left side of the heart back to the more compliant lung. 2. We probed whether, and through which mechanisms, a redistribution of blood from the lungs to the left heart occurs during vertical displacement and compensates for reduced venous return. 3. We investigated 16 normal volunteers with Doppler-echocardiography during 20 degrees, 40 degrees and 60 degrees head-up tilting. Tilting was stopped at 10 min in 10 subjects (group 1) and at 45 min in 6 subjects (group 2). 4. At 10 min we observed a reduction in right ventricular diastolic dimension and left ventricular end-diastolic pressure, as estimated by the difference between the duration of the pulmonary venous flow during atrial contraction (Z wave) and that of the mitral A wave. We also recorded a decrease during systole (X wave) and an increase during diastole (Y wave) of the pulmonary venous forward flow velocity. These variations were evident at 20 degrees and became progressively greater with increasing degrees of tilting. In group 2, changes at 10 min and at 45 min for any degree of displacement were similar. 5. A decrease in right ventricular dimensions (ventricular interdependence) and underfilling of the lung compartment due to volume redistribution to the periphery (diminished lung contribution to pericardial constraint) augment compliance within the pericardial space, reduce downstream pressure for pulmonary venous return and move the pulmonary venous flow predominantly to ventricular diastole, allowing diastolic filling. 6. During head-up tilting a favourable interaction between heart and lungs increases compliance within the pericardial space and facilitates redistribution of blood from the lungs, resulting in a sustained compensation for the reduced venous return.

Relation between exercise-induced left ventricular wall motion abnormalities and coronary artery disease in hypertensive patients: effects of blood pressure normalization.

In hypertension, several factors disturb coronary circulation and the metabolic reserve of the heart. This study was undertaken to test whether in hypertensive patients global and regional left ventricular (LV) function is related during exercise to the presence of significant coronary stenosis and whether lowering of coronary perfusion pressure through rapid normalization of the diastolic pressure may modify the dynamics of the left ventricle. Thirty-five patients with mild to moderate hypertension undergoing coronary angiography for the evaluation of chest pain were included in the study; upright bicycle exercise echocardiography tests were performed without therapy and 1 day later 1 h after sublingual administration of nifedipine. LV ejection fraction and regional wall motion scores were evaluated and compared at baseline, peak exercise, immediate postexercise, and recovery phases in each test through digital on-line storing of echocardiographic images. Twenty-one patients had normal coronary arteries (group 1) and 14 significant coronary stenoses (group 2); age, gender, heart rate, blood pressure, left ventricular diameter and mass index, and ejection fraction were similar in the two groups. At peak exercise LV ejection fraction slightly increased in group 1, whereas it slightly decreased in group 2 (both during the test without therapy and after nifedipine administration). All patients in group 1 had normal left ventricular wall motion during exercise; 13 of 14 patients in group 2 had LV wall motion abnormalities at peak exercise. Nifedipine did not produce any effect on LV regional wall motion in group 1, but it induced significant changes in LV regional wall motion in seven patients in group 2. Changes in LV wall motion between the two test groups were related to the number of the stenotic coronary vessels: the normal exercise test before and after therapy and the two normalized tests after nifedipine administration were in fact observed in patients with one-vessel disease, whereas worsening or changes in the site of ischemia were observed only in patients with multivessel disease. Regional and global left ventricular dynamics during exercise is mainly dependent on the existence of significant coronary artery disease. Rapid decrease of blood pressure does not alter the regional dynamics of the left ventricle during exercise in patients without coronary artery disease, but it may induce normalization, worsening, or changes in the site of wall motion abnormalities in hypertensives with significant coronary stenoses.

[Biventricular-pulmonary interaction as the prime mechanism in the adaptation of the human heart to orthostatic posture]. / Interazione biventricolo-polmonare quale primo meccanismo di adattamento del cuore umano alla posizione ortostatica.

The purpose was to identify the basic circulatory adjustments to the erect position in man and what the role may be of the heart-lung coupling. Requirements for this study are that: subjects be normal, changes in posture be gradual; pulmonary venous flow, ventricular filling and output be assessed; the methods be noninvasive. In 10 normal men (mean age 34 +/- 8 years) the flow pattern in the right upper pulmonary vein and through the atrioventricular mitral valve, and the right and left ventricular (RV and LV) end-diastolic dimensions were assessed with Doppler echocardiography, in the supine position, after 20, 40 and 60 degrees tilting for 10 min. At 20 degrees displacement: blood pressure, heart rate, stroke volume and LV dimension did not change: RV dimension reduced: pulmonary venous forward flow velocity diminished during systole (X wave) and rose in diastole (Y wave); E wave velocity of the mitral flow and the E/A ratio reduced (consistent with a lower atrioventricular pressure gradient); difference between duration of the pulmonary venous flow reversal during atrial contraction (Z wave) and duration of the mitral A wave (the difference is an index of LV end-diastolic pressure) also diminished, suggesting an improvement of LV compliance. Tilting at 40 and 60 degrees were associated with increase in heart rate and diastolic blood pressure; decrease in systolic blood pressure and stroke volume; reduction of diastolic dimension of both ventricles; some enhancement of the flow changes already described. X was related to stroke volume while supine (r = 0.75; p < 0.01) and not during tilting; at any level of tilting, X/Y ratio was inversely related to the E/A ratio and directly related to the difference in duration between Z and A. During vertical displacement, blood shifts from lungs to systemic circulation resulting in: contribution to replenishment of the arterial side of the circuit; enhancement in LV compliance, due to reduction of RV diastolic volume (interdependence) and pericardial constraint; facilitation and predominance of blood drainage for the lungs during ventricular diastole. Thus, the basic adaptation to erect positioning in man seems to be a mechanical one, mainly consisting of an interplay between heart and lungs. Increase in heart rate and vasoconstriction appear to be supportive mechanisms at more vertical postures.

Influences of aortic pressure gradient and ventricular septal thickness with systolic coronary flow in aortic valve stenosis.

This study evaluates flow patterns of the left anterior descending and circumflex coronary arteries by multiplane transesophageal echocardiography in 25 patients with aortic valve stenosis, and assesses the relation between coronary flow characteristics and anatomic and hemodynamic parameters.

Straddling endoventricular pericardial patch in mitral valve repair with the sliding leaflet technique.

Calcification of the mitral annulus is always a technical complication in mitral surgery and standard procedures are often difficult to perform; mitral valve replacement can be dangerous with a high risk of perioperative heart rupture, and reconstructive surgery is often contraindicated. Nevertheless in this case of posterior leaflet prolapse with annular calcification valve repair was performed, after complete calcium debridement causing annulus disruption and atrio-ventricular discontinuity, by means of a straddling atrio-ventricular pericardial patch and the sliding leaflet technique.

Acute effects of dynamic cardiomyoplasty on ventricular geometry and left ventricular filling detected by transesophageal doppler echocardiography.

We investigated 7 patients with chronic congestive heart failure undergoing dynamic cardiomyoplasty with intraoperative transesophageal echocardiography. Biventricular wrapping acutely modified right or left ventricular geometry, but did not induce acute restriction to left ventricular filling.

Acute filling pattern changes of the failing left ventricle after captopril as related to ventricular structure.

In congestive heart failure captopril modifies the left ventricular filling pattern mainly by unloading the heart. We investigated whether the structural characteristics of the left ventricle may influence the acute effects of captopril on this pattern in patients with untreated hypertensive (H group, 6 patients) or idiopathic (I group, 14 patients) cardiomyopathy. We evaluated changes of pulsed Doppler mitral flow, of systemic arterial and wedge pulmonary pressures 40 min after 25 mg captopril administered sublingually, and correlated these changes with the M-mode echocardiographic relative wall thickness index (h/r). Baseline mean arterial pressure (H = 137 +/- 20 mm Hg, mean +/- SD, I = 95 +/- 19 mm Hg; p < 0.001), and h/r (H = 0.38 +/- 0.03, I = 0.28 +/- 0.09; p < 0.05) were greater in the high blood pressure group; wedge pressure, echocardiographic biplane ejection fraction, and Doppler indexes of the left ventricular filling were similar in the two populations. After captopril, ejection fraction did not change significantly, mean arterial pressure decreased significantly in hypertensive patients (H group, baseline = 137 +/- 20, captopril = 119 +/- 10, p = 0.02; I group, baseline = 95 +/- 19, captopril = 90 +/- 24, p = nonsignificant), and the wedge pressure was reduced by the same extent in both groups (H group, baseline = 27.7 +/- 3, captopril = 21 +/- 7, p < 0.05; I group, baseline = 20 +/- 12, captopril = 15 +/- 8, p < 0.05). In the H group early mitral flow increased [(E wave integral) x (mitral annulus area)] by 38 +/- 15%, and was almost steady in the I group (-1.3 +/- 30%; group H vs. I = p < 0.01); late mitral flow [(A wave integral) x (mitral annulus area)] showed a pattern exactly opposite to this (H = +0.4 +/- 40%, I = +38 +/- 19; p < 0.01). In the whole population there was a significant correlation between the early/late flow ratio variations and baseline h/r (r = 0.6, p < 0.05). In chronic congestive heart failure, changes in left ventricular filling with captopril are related to h/r: a higher index, as recorded in the H group, is associated with "true normalization' of the filling pattern after captopril; a lower index, as recorded in the I group, is associated with "pseudonormalization' despite a similar decrease of left ventricular filling pressure.