Search

Stromatolites form by the close interaction between the microbial activity and the environment in a great range of depositional settings resulting in heterogeneous growth morphologies and fabrics. The link between morphological diversity and internal structure of stromatolites to environments is not straightforward due to the dual influence at all scales of biological and physico-chemical factors. Specifically, in low energy settings biological controls are the dominant in influencing stromatolites, as suggested from modern analogues.In this study we examine geometries and fabrics of stromatolites from the mixed carbonate-siliciclastic marginal lacustrine succession of the Yacoraite Formation (Cretaceous-Paleogene) in Tres Cruces (Salta Basin). The outcrops that extend along a W-E transect of 10 kilometres, provide exceptional exposure allowing to analyse the geometries and lateral continuity of the stromatolite beds. Current stratigraphic research interprets the Yacoraite succession as a closed, saline lake with two evolutionary stages. The first stage, dominated by carbonate production, represents a shallow-water perennial lake with moderate wave energy. The second stage corresponds to a rapidly fluctuating, low-water energy ephemeral lake with abundant fine-grained siliciclastics and frequent subaerial events. This change is related to climatically driven lake-level fluctuations. Marked differences in the lateral continuity of the stromatolite beds and their associated facies have been observed along the Yacoraite succession. In the perennial lake, the stromatolite beds overlie oolitic facies and can be traced laterally for several kilometres whereas in the ephemeral lake the stromatolites grow on both oolitic and siliciclastic facies and form discontinuous levels along hundreds of meters that pass laterally into the oolitic facies. Stromatolite growth morphologies, however, show a more homogeneous distribution that does not clearly reflect the evolutionary changes of the Yacoraite paleolake. Generally, the stromatolites of the perennial lake exhibit planar morphologies that pass upwards into coalescent domes forming structures that range in height from few decimetres up to 1 m. The stromatolites of the ephemeral lake are mainly planar, wavy (dm-scale) or domes that are coalescent and form tabular decimetric structures. Morphological vertical zonation is rare. The change in stromatolite morphology can be tentatively attributed to decreased accommodation and water energy conditions. However, this interpretation needs to be taken carefully considering that all these types of stromatolite morphologies have been observed along the Yacoraite succession, regardless of the lake stage. Stromatolites show mainly well-developed internal lamination. Their microfabrics are either fine-grained (micritic, clotted and/or filamentous) or formed by combinations of fine-grained and sparry layers composed of fibrous calcite crusts, calcite spherulites and/or shrubs.Further work will intend to better understand the spatial and temporal distribution of the stromatolite geometries and fabrics along the Yacoraite Formation to shed light on the influence that environmental and biotic factors exert in stromatolite macro, meso and microscale in low-energy lacustrine settings.

The interplay between carbonate production and siliciclastic input in marine mixed depositional systems results in spatially complex distribution of facies. In this study, we investigate this interplay in a lacustrine setting to explore hypotheses for the facies distribution and stratigraphic architecture in such settings. The Yacoraite Formation (Maastrichtian-Danian) is a mixed lacustrine carbonate-siliciclastic succession within the Salta Group in the Salta rift Basin (Argentina). The Yacoraite Fm has been thoroughly characterized in the southern part of the basin (Metán-Alemania sub-basins), whereas the northern sub-basin of Tres Cruces, focus of this study, remains largely understudied. In this project we applied high-resolution stratigraphic and sedimentological analyses to characterize in detail the depositional environment and the stratigraphic architecture of the Yacoraite Fm. Facies are mainly represented by lacustrine marginal and littoral associations. The facies associations, their distribution and stacking pattern are interpreted to reflect deposition in a predominantly shallow water balanced-fill lake basin type. Littoral and sub-littoral facies associations are dominated by oolitic, skeletal and microbial carbonates, frequently intercalated with fine-grained siliciclastic facies, ranging from mudstones and siltstones deposited in mudflats, shoreline sandstone deposits and distal profundal shales. The Yacoraite Fm is tentatively subdivided in two intervals. The lower part (lower 100 m) is characterized by carbonate-dominated facies, showing a marked and regular cyclicity, with metric-scale sequences of carbonate-dominated facies overlying fine-grained siliciclastics and mudstone-wackestone. These cycles are interpreted as shallowing-upwards cycles, composing the regressive hemicycles of metric-scale Transgressive-Regressive (T-R) cycles. These cycles are often asymmetric and result from lacustrine expansion-contraction cycles, controlled by climatically influenced lake-level fluctuations. The middle-upper part (m 100 to 220 circa) is dominated by siliciclastic facies and is characterized by a decrease in regularity of cyclicity, with high frequency T-R cycles being asymmetric and often lacking the transgressive hemicycles. Frequent desiccation cracks and tepees mark the top of the regressive hemicycles in the middle to upper part, indicating repeated sub-aerial exposures. Our observations are in line with the hypothesis that alternating phases of deposition between clastic-dominated facies and carbonate-dominated facies are the result of climatically driven lake-level fluctuations. Carbonate production is enhanced during arid climatic phases (lake contraction), whereas siliciclastic-dominated facies are mainly deposited during humid phases, coeval with an increase of water inflow and sediment input into the lake, corresponding to expansion phases. Based on our sedimentological and stratigraphical analysis the evolution of the lake system has been inferred, with the identification of two lake stages in the evolution of the Yacoraite paleo-lake. A first lake stage is characterized by a perennial lake system that progressively changes into a more rapidly fluctuating ephemeral setting; this shift appears to be gradual as there is no clear stratigraphic expression corresponding to the transition itself. Climate appears to be the primary control on the stratigraphic architecture, with rapid lake-level variations resulting in sharp facies transitions from carbonate to siliciclastic facies and prevalently stratigraphic mixing. Compositional mixing is limited to the littoral facies, due to the local presence of siliciclastic input sources by riverine inflows into the Yacoraite paleo-lake system.

The first pre-Quaternary representative of Alismataceae from South America is reported based on achenes of Sagittaria montevidensis from the Palo Pintado Formation (upper Miocene) in the south of Salta Province, Argentina. Achenes are laterally compressed, have a lateral beak and a single recurved seed inside them. The fruits were found both in the base (10 Ma) and the top of the formation (~5 Ma), suggesting similar environmental conditions during this time period. A cursory review of the Alismataceae family in the fossil record, with a special interest in those South American reports is given. During the Oligocene–Miocene Sagittaria may have arrived from tropical Africa to South America and thence to North America.

Blood stasis is the main cause of left atrial thrombosis (LAT) in atrial tachyarrhythmias. The high-velocity flow inside the left atrium, due to mitral valve regurgitation, may prevent clot formation but the topic has never been investigated in large-scale studies. The aim of our study was to evaluate whether the presence and degree of mitral regurgitation have a protective role against LAT risk.A total of 1302 consecutive adult patients with paroxysmal or persistent atrial fibrillation or flutter undergoing cardioversion, submitted to transesophageal echocardiography, were retrospectively enrolled in the study. The study population was divided into three groups according to the mitral regurgitation degree: absent, mild-to-moderate and severe.Among 1302 patients enrolled in the study, patients without mitral regurgitation were 248 (19%), those with mild-to-moderate 970 (75%), whereas 84 had severe mitral regurgitation (6%). LAT incidence was significantly lower in patients with severe mitral regurgitation compared with those with mild-to-moderate (mitral regurgitation) (2.4 vs. 8.9%, P 0.05), and similar to subjects without mitral regurgitation (2.4%).Despite patients with severe regurgitation having clinical and echo characteristics predisposing to LAT (higher age, heart failure, higher atrial size, lower ventricular function) thrombosis prevalence was significantly lower than for those with mild-to-moderate mitral regurgitation. The percentage of LAT in severe mitral regurgitation cases was very low and similar to that of cases without regurgitation which were characterized by lower age, normal left ventricular function or other risk factors, reinforcing the hypothesis of a protecting role against atrial thrombosis of mitral regurgitation.

Las rocas sedimentarias continentales que constituyen la Formación Palo Pintado, de edad del Mioceno tardío, afloran en la provincia de Salta y suscitan un gran interés paleoclimático, dadas las condiciones ambientales reinantes durante ese intervalo geocronológico. Los registros geológicos y paleobotánicos sugieren que durante la acumulación de las rocas sedimentarias de la Formación Palo Pintado (cuenca de Angastaco) habrían existido condiciones más húmedas en comparación a las de otras formaciones cercanas y coetáneas, por ejemplo, la Aloformación Playa del Zorro y la Formación Chiquimil (Mioceno tardío, provincias de Catamarca y Tucumán) y las formaciones Salicas y Toro Negro (Mioceno tardío, provincia de La Rioja). En este estudio se analizaron el margen y el área foliar de las hojas fósiles contenidas en las rocas de la Formación Palo Pintado, a fin de obtener la temperatura media anual (TMA) y la precipitación media anual (PMA). Los valores resultantes fueron los siguientes: TMA=23,98 °C y PMA=330,8 mm. Estos resultados se condicen con la interpretación de diferentes autores quienes consideran que la Formación Palo Pintado se habría depositado bajo un ambiente relativamente húmedo, posiblemente como consecuencia de las lluvias caídas localmente en la región de la cuenca de Angastaco. The continental sedimentary rocks that constitute the Palo Pintado Formation of the late Miocene from Salta province, presents a great paleoclimatic interest due to the environmental conditions prevailing during this geochronologic interval. The geological and paleobotanical data suggest that during the sedimentary rocks accumulation of the Palo Pintado Formation (Angastaco Basin), wetter conditions would have existed comparing with other nearby and contemporary Formations, for example the Playa del Zorro Aloformation (late Miocene of Catamarca) and the Chiquimil (late Miocene of Tucumán), Salicas and the Toro Negro Formations (both from the late Miocene of La Rioja). In this study, the margin and the foliar area of the leaves contained on rocks from the Palo Pintado Formation are analyzed, in order to obtain the mean annual temperature (MAT) and the mean annual precipitation (MAP). The resulting values were: 23.98 °C and 330.8 mm. These results are coincident by the interpretation of different authors, who consider that the Palo Pintado Formation would have been deposited under a relatively humid environment, possibly as a consequence of the rains that affected locally the Angastaco basin region. Fil: Robledo, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina Fil: Horn, Maricel Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Galli, Claudia Inés. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina Fil: Anzótegui, Luisa Matilde. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina

The Ramadas Volcanic Center on the eastern margin of the central Andean Puna plateau along the Olacapato-El Toro lineament in Argentina erupted a rare strongly peraluminous Mn-rich garnet-bearing rhyolitic tuff in the late Miocene. The voluminous ashes from this eruption, which are distinctive in having euhedral spessartine almandine garnets (Alm70–72Sps22–26Grs2–4Prp0.5–1) as their only phenocryst, are widely dispersed in the Andean foreland. Among these tuffs are those in the Guanaco Formation foreland basin sediments along the Xibi-Xibi and Los Alisos rivers in the Rio Grande de Jujuy basin and the Metán Valley, some 100–200 km east of the Ramada Volcanic Center. The co-occurrence of tubular to cellular pumice fragments and blocky glass shards in an ash matrix in these tuffs is interpreted as indicating that they erupted in an initial vent-opening event with pulsating pyroclastic surges at the initiation of the strong Plinian eruption of the Ramada Volcanic Center. New Ar/Ar ages from the Guanaco Fm. glass shards agree with fossil ages in placing the eruption at ~6.3 ± 0.3 Ma. A number of distinctive chemical, isotopic and mineralogical features including Mg-rich biotite and Mg-hastingsite xenocrysts of the Guanaco Formation and Ramadas Volcanic Center tuffs are consistent with the melt having been derived by extensive crystallization of a mantle-derived mafic shoshonitic series magma contaminated by assimilation/dehydration melts of metapelitic sediment and the Puna crust. Distinctive chemical features include whole rock SiO2 contents of ~75–76% wt%; A/CNK indices >1.2; low Ca, Mg, Ti, and Fe concentrations; steep REE patterns with extreme negative Eu anomalies; low Ba, Sr, LREE and high Cs, Rb, U concentrations; and recalculated initial ratios of 87Sr/86Sr at ~0.7119 and 143Nd/144Nd of ~0.5123 at 6.3 Ma. The erupted magma has a transitional chemical character between those of the ~11 Ma Mn-rich garnet-bearing Coyaguayma ignimbrites to the north and the ~6 Ma Cerro Galan ignimbrites to the south. Unlike these crystal-rich ignimbrites, the Ramadas tuff records the extraction of an extensively fractioned melt from a plagioclase, K-feldspar, quartz and biotite-bearing mush with accessory titanomagnetite and apatite. In line with existing experimental studies on Mn-rich garnets and comparisons with the Coyaguayma ignimbrite, pre-eruption crystallization of the rhyolite segregated from the mush likely occurred at ~800° to 720 °C at a depth of no

El presente material es producto de la experiencia en cátedras del área Álgebra y cursos de ingreso y la previa elaboración de apuntes para Álgebra, Cálculo Numérico y Geometría Analítica, Matemática I. Recopila, unifica, amplía y mejora el material existente. Presenta todos los temas de esas asignaturas, con una base teórica sólida, práctica, aplicaciones y motivaciones, integrando y relacionando contenidos. Algunos temas son comunes y de igual nivel en las tres. Otros difieren en profundidad y hay subtemas abordados solo en alguna de ellas. Por ello, sugerimos al estudiante que utilice el libro con diferente recorrido de acuerdo a su interés. Es texto de las materias mencionadas y puede servir de consulta o referencia para las asignaturas Probabilidades, Estadística e inicio para otras del área Álgebra., Facultad de Ciencias Exactas

Quality insurance processes use goal attainment as criteria for funding occupational therapist (OT) services in Switzerland. As this is an important issue for the Swiss OT association, a continuing professional development (CPD) programme was implemented to assist OTs to set occupation-focused and person-centred goals. This qualitative study was conducted using three focus groups to understand the difficulties met by clinicians in the context of setting goals. Sixteen OTs reported that time constraints and routines make it difficult to define and formulate goals well. The problem is not a lack of knowledge, but to change one’s habits and practices the results. A CPD course was developed, adapted in three languages and implemented. Evaluation of the course indicates that it helps the participants to better understand the need for writing goals that are person-centred and occupation-focused. This course may be supportive of improved occupational-based goal setting in other countries.

Aims The aim of this study, undertaken in patients who underwent mitral valve (MV) repair surgery, was to evaluate the accuracy of pre-operative three-dimensional (3D) transthoracic echocardiography (TTE) in the evaluation of MV pathology in cases with simple or complex lesions. Methods and results Two hundred consecutive patients with severe mitral regurgitation due to degenerative MV prolapse underwent a complete 3DTTE the day before surgery. Three-dimensional TTE data were compared with MV surgical inspection. Three-dimensional echocardiography was feasible in a relatively short time (5 ± 3 min) with good (67%) and optimal (21%) imaging quality in the majority of cases. Three-dimensional TTE allowed an accurate identification (95% accuracy) of all MV lesions. Seventy-three (36.5%) patients had simple lesions at 3DTTE and 71 of them (97.2%) underwent a simple surgical procedure; 127 (63.5%) had complex lesions at 3DTTE and, in these cases, surgeons performed either simple procedures (48%) or complex procedures (47.2%) or valve replacement in 4.7% (after a first attempt for repair). Conclusion Three-dimensional TTE is feasible, not time-consuming, and accurate in identifying cases with simple vs. complex MV lesions.

A new generation of transoesophageal echocardiographic probes with a novel matrix array technique has been recently introduced, allowing three-dimensional (3D) presentation of cardiac structures in real-time. This new tool may potentially provide fast and complete 3D information about cardiac structures improving spatial orientation and overcoming limitations of offline 3D technologies. The aim of this study was to demonstrate the feasibility and usefulness of real-time 3D transoesophageal echocardiography (TOE) for the intraoperative evaluation of cardiac surgery procedures. One-hundred patients underwent transoesophageal echocardiographic examination during cardiac surgery as a part of their routine clinical practice. In the intraoperative pre- and post-cardiopulmonary bypass periods complete 2D and 3D transoesophageal examinations were performed. Feasibility and duration of examinations, and immediate additional anatomical value of 3D versus 2D-TOE were annotated intraoperatively. Image quality, additional clinical value of 3D- compared to standard 2D-TOE and the accuracy in the description of mitral valve pathology by a surgeon and an echocardiographer were evaluated off-line. No complications related to transoesophageal examination occurred and successful intubation was achieved in all 100 patients. Therefore, 200 examinations were performed and analysed considering the pre- and post-cardiopulmonary bypass periods. The mean number of acquisitions per patient was 16 +/- 14, including 3D real-time, zoom, full-volume and colour full volume modalities. The duration of the 3D examination was 16 +/- 10 min and the mean image quality score 2.8 +/- 0.7 (in a scale 1-4). In 36 out of 100 cases (36%) 3D-TOE provided additional anatomical information. The surgeon evaluated 3D images easier and more accurately than 2D images (88% vs. 76% in the evaluation of mitral valve scallop). Real-time 3D TOE may be used routinely for the intraoperative evaluation of cardiac surgery. Imaging with this new probe facilitates intraoperative evaluation of several surgical procedures with an additional clinical value in selected cases.

Objectives Transesophageal echocardiography (TEE)-guided cardioversion has been demonstrated to be well tolerated in patients with atrial fibrillation. Guidelines do not suggest whether patients with severe spontaneous echocontrast (SEC) and sludge can be safely submitted to cardioversion. In our observational study, we analyzed the prevalence of SEC in patients with atrial fibrillation taking different anticoagulant therapies, the incidence of embolic complications after cardioversion in patients with severe SEC or sludge and the usefulness of TEE in reducing embolic complications in these patients. Methods The study population consisted of 1104 patients with atrial fibrillation, candidates for cardioversion and submitted to TEE. They were divided into four groups: effective conventional oral anticoagulation, short-term anticoagulation, subtherapeutic anticoagulation and effective oral anticoagulation for less than 3 weeks for different clinical reasons. Cardioversion was postponed in patients with atrial thrombosis; in the presence of severe SEC, the decision to cardiovert was left to the treating physician. Results Atrial thrombosis was detected in 65 (5.9%) patients, and SEC was detected in the majority of patients independent of the anticoagulant scheme; in 131 patients, it was severe and, in this group, sludge was identified in 57 patients. Cardioversion was performed in 922 patients and was successful in 849 (including 22 patients with severe SEC and four with sludge) with one minor embolic event. Conclusion SEC and sludge are frequently observed in patients with atrial fibrillation undergoing cardioversion. A TEE approach may prevent the risk of embolic events. In the presence of severe SEC and sludge, treating physicians frequently postpone cardioversion, even though in the patients submitted to cardioversion, no events were observed.

The evaluation of right ventricular (RV) systolic function is important for its clinical and prognostic value but difficult to obtain due to RV complex anatomy. Aims of this study were to evaluate the feasibility of a routine use of RV fractional shortening area (FSA), systolic excursion (TAPSE) and peak systolic velocity (PSV) of tricuspidal annular motion in a large series of cases (900 pts), to determine the values in normal subjects (150) and in patients (750) with different pathologies and to correlate these indexes to clinical and echo-Doppler variables. FSA (50.3+/-10% vs 54.6+/-9% p

The radiofrequency maze procedure achieves sinus rhythm in 45%–95% of patients treated for atrial fibrillation. This retrospective study evaluates mid-term results of the radiofrequency maze—performed concomitant to elective cardiac surgery—to determine sinus-rhythm predictive factors, and describes the evolution of patients' echocardiographic variables. From 2003 through 2011, 247 patients (mean age, 64 ± 9.5 yr) with structural heart disease (79.3% mitral disease) and atrial fibrillation underwent a concomitant radiofrequency modified maze procedure. Patients were monitored by 24-hour Holter at 3, 6, 12, and 24 months, then annually. Eighty-four mitral-valve patients underwent regular echocardiographic follow-up. Univariate and multivariate analysis for risk factors of maze failure were identified. The in-hospital mortality rate was 1.2%. During a median follow-up of 39.4 months, the late mortality rate was 3.6%, and pacemaker insertion was necessary in 26 patients (9.4%). Sinus rhythm was present in 63% of patients at the latest follow-up. Predictive factors for atrial fibrillation recurrence were arrhythmia duration (hazard ratio [HR]=1.296, P=0.045) and atrial fibrillation at hospital discharge (HR=2.03, P=0.019). The monopolar device favored maze success (HR=0.191, P Concomitant radiofrequency maze procedure provided remarkable outcomes. Shorter preoperative atrial fibrillation duration, monopolar device use, and prompt treatment of arrhythmia recurrences increase the midterm success rate. Early sinus rhythm restoration seems to result in better left ventricular ejection fraction recovery.

Background. Maze procedure aims at restoring sinus rhythm (SR) and atrial contractility (AC). This study evaluated multiple aspects of AC recovery and their relationship with SR regain after ablation.Methods. 122 mitral and fibrillating patients underwent radiofrequency Maze. Rhythm check and echocardiographic control of biatrial contractility were performed at 3, 6, 12, and 24 months postoperatively. A multivariate Cox analysis of risk factors for absence of AC recuperation was applied.Results. At 2-years follow-up, SR was achieved in 79% of patients. SR-AC coexistence increased from 76% until 98%, while biatrial contraction detection augmented from 84 to 98% at late stage. Shorter preoperative arrhythmia duration was the only common predictor of SR-AC restoring, while pulmonary artery pressure (PAP) negatively influenced AC recuperation. Early AC restoration favored future freedom from arrhythmia recurrence. Minor LA dimensions correlated with improved future A/E value and vice versa. Right atrial (RA) contractility restoring favored better left ventricular (LV) performance and volumes.Conclusions. SR and left AC are two interrelated Maze objectives. Factors associated with arrhythmia “chronic state” (PAP and arrhythmia duration) are negative predictors of procedural success. Our results suggest an association between postoperative LA dimensions and “kick” restoring and an influence of RA contraction onto LV function.

Aim Transient coronary artery occlusion during percutaneous transluminal coronary angioplasty may cause left ventricular diastolic dysfunction. The aim of this study was to evaluate the effect of left anterior descending, left circumflex and right coronary artery balloon occlusion on right ventricular diastolic function. Methods Thirty-five patients with single-vessel coronary artery disease and no previous myocardial infarction were selected. Left and right ventricular filling pressures were monitored by Doppler echocardiography and haemodynamic monitoring. This was performed during and immediately after 60 s of coronary balloon occlusion of the left anterior descending artery in 21 cases (Group 1), the left circumflex artery in eight cases (Group 2) and the right coronary artery in six cases (Group 3). Doppler analysis of left and right ventricular filling included peak velocity of early (PFVE) and late ventricular filling (PFVA) and PFVE to PFVA ratio (PFVE/PFVA). Results In all three groups, balloon inflation induced a significant increase in left and right filling pressures ( P

Our results support the hypothesis that in aortic valve stenosis, the pattern of systolic coronary flow is related to the aortic pressure gradient and interventricular septal thickness. A hypertrophic septum interfering with systolic aortic pressure facilitates the increase in intramural resistances during systole in the left anterior descending artery territory. Surgical repair reduces the aortic gradient and increases systolic coronary flow, but the influence on ventricular septal thickness is not immediate; thus, maintenance of adequate aortic systolic pressure is of great importance in improving coronary perfusion.

The Doppler formulas currently used for right ventricular systolic pressure (RVSP) evaluation include right ventricular-right atrial (RV-RA) gradient and RA pressure. The former is expressed by the velocity of the trans-tricuspid regurgitant flow; the latter is generally assumed and is different from one formula to another. In 110 patients with cardiac disease with normal or elevated pulmonary pressure, we tested a new echo-Doppler formula for the evaluation of RVSP based on the estimation of RA pressure by means of the inferior vena cava collapsibility index (IVCCI) and compared this method with two traditional formulas (methods A and B) and with cardiac catheterization values. Patients were classified into three groups on the basis of IVCCI (group 145%, group 2 between 35% and 45%, and group 335%). RVSP was evaluated by method A (RV-RA gradient + 10), method B (RV-RA gradient x 1.1 + 14), and our new method, method C, which assigns 6, 9, and 16 mmHg to RA pressure in the presence of normal (45%), moderately reduced (between 35% and 45%), or markedly reduced (35%) IVCCI, respectively. IVCCI correctly identified RA pressure in the three groups (group 1, 6.8 mmHg; group 2, 10.8 mm Hg; and group 3, 13.1 mmHg); a high correlation existed between Doppler-derived and invasively determined RV-RA gradient (r = 0.99). Method C improved noninvasive estimation of RVSP in groups 1 and 3 compared with the other methods; in group 2, Doppler estimation of RVSP by methods A and C were comparable, whereas method B significantly overestimated the actual values.(ABSTRACT TRUNCATED AT 250 WORDS)

Right ventricular (RV) dimensions and function are of diagnostic and prognostic importance in cardiac disease. Because of the peculiar morphology of the right ventricle, 2-dimensional echocardiography has several limitations in RV evaluation. Recently, new 3-dimensional transthoracic echocardiographic software adapted for RV morphology was introduced. The aims of this study were to evaluate the feasibility of 3-dimensional RV analysis in a large population and to compare and correlate 3-dimensional RV data with classic 2-dimensional and Doppler parameters, including tricuspid annular plane systolic excursion and peak systolic velocity on Doppler tissue imaging, RV fractional shortening area, RV stroke volume (by the Doppler method), and pulmonary arterial systolic pressure. Two hundred subjects were studied: 48 normal controls and 152 patients with valvular heart disease (104 patients), idiopathic dilated cardiomyopathy (20 patients), or pulmonary hypertension (28 patients). The mean times for 3-dimensional acquisition and 3-dimensional reconstruction were 3 +/- 1 and 4 +/- 2 minutes, respectively. Imaging quality was good in most cases (85%). The mean RV diastolic and systolic volumes were 103 +/- 38 and 46 +/- 28 ml, respectively. The RV ejection fraction (RVEF) was correlated negatively with pulmonary arterial systolic pressure and positively with tricuspid annular plane systolic excursion, peak systolic velocity, and fractional shortening area. The pathologic group was characterized by larger RV volumes and lower RVEFs. Three-dimensional echocardiography clearly showed that in the pathologic group, patients with pulmonary hypertension had the largest RV volumes and the lowest RVEFs and that those with idiopathic dilated cardiomyopathy were characterized by RVEFs lower than those of patients with valvular disease. In conclusion, this new quantitative 3-dimensional method to assess RV volumes and function is feasible, relatively simple, and not time consuming. Data obtained with 3-dimensional analysis are well correlated with those obtained by 2-dimensional and Doppler methods and can differentiate normal and pathologic subjects.

We investigated the acute effects of nifedipine (10 mg orally) on renin and systemic hemodynamics in twelve patients who had severe hypertension (diastolic values averaging 114 mm Hg) with unilateral renal artery stenosis (angiography) and hyperreninemia. Plasma renin activity was determined from blood samples drawn from the aorta and from both renal veins, so that "ischemic lateralization" could be evaluated through appropriately derived indexes. Nifedipine promptly and significantly lowered aortic pressure in all patients. At 30 minutes maximal circulatory responses were recorded, which consisted of a 22% decrease in mean aortic pressure (from an average of 144.6 +/- 15 mm Hg to an average of 113 +/- 11 mm Hg), a 44% reduction of systemic vascular resistance (from 2162 +/- 540 dynes.sec.cm-5 to to 1205 +/- 279 dynes.sec.cm-5), a 33% rise in cardiac index (from 2920 +/- 970 ml/min/m2 to 3875 +/- 986 ml/min/m2). These effects were still evident, although somewhat tempered, after 180 minutes of continuous monitoring; they were qualitatively and quantitatively similar to those reported by some authors in persons with primary hypertension with similar levels of blood pressure. After nifedipine was given, renin activity of the systemic blood rose significantly, because of a potentiated release from the kidney with arterial stenosis. This effect, which was inferred as being due to further reduction of the renal perfusion pressure, improved the significance of "ischemic lateralization" indexes and supported the diagnosis of renovascular hypertension in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic valve diseases, hypertension, and connective tissue disorders may be causes of ascending aortic aneurysms. Aortic enlargement monitoring is essential for surgical timing and for operative design. In this regard, several imaging techniques may have limitations: magnetic resonance is not widespread and is expensive, computed tomography uses radiation, and transesophageal echocardiography is a semi-invasive method. The aim of this study was to analyze the feasibility of transthoracic echocardiography in the evaluation of aortic dimensions and its accuracy in comparison with multidetector computed tomography. In 44 patients with known ascending aortic aneurysms, transthoracic echocardiographic and computed tomographic measurements were obtained and compared at different levels: the annulus, sinuses of Valsalva, sinotubular junction, ascending aorta, and aortic arch. Transthoracic echocardiographic diameters were obtained in all patients, apart from the aortic arch, which was measured in 40 cases. Transthoracic echocardiographic and computed tomographic diameters correlated significantly (p

Objectives The aim of this study, undertaken in patients who underwent mitral valve (MV) repair surgery, was to evaluate the feasibility and accuracy of 3-dimensional (3D) transthoracic (TTE) and transesophageal (TEE) echocardiography in the evaluation of MV pathology. Background A pre-operative assessment of MV anatomy is essential to surgical design in patients undergoing MV repair. Although 2-dimensional (2D) echocardiography provides precise information regarding MV anatomy, 3D TTE and 3D TEE could increase the understanding of MV apparatus and individual scallop identification. Methods One-hundred-twelve consecutive patients with severe mitral regurgitation due to MV prolapse underwent a complete 2D and 3D TTE the day before surgery and a complete 2D and 3D TEE in the operating room. Echocardiographic data obtained by the different techniques were compared with surgical inspection. Results Three-dimensional techniques were feasible in a relatively short time (3D TTE: 7 +/- 4 min; 3D TEE: 8 +/- 3 min), with good (3D TTE 55%; 3D TEE 35%) and optimal (3D TTE 21%; 3D TEE 45%) imaging quality in the majority of cases. Three-dimensional TEE allowed more accurate identification (95.6% accuracy) of all MV lesions in comparison with other techniques. Three-dimensional TTE and 2D TEE had similar accuracies (90% and 87%, respectively), whereas the accuracy of 2D TTE (77%) was significantly lower. Conclusions Three-dimensional TTE and TEE are feasible and useful methods in identifying the location of MV prolapse. They were superior in the description of pathology in comparison with the corresponding 2D techniques and should be regarded as an important adjunct to standard 2D examinations in decisions regarding MV repair.

Transesophageal echocardiography (TEE) is the method of choice for the evaluation of the left atrium and of left atrial appendage (LAA) thrombosis. However, the anatomy of the left appendage is complex and reverberations from anatomical structures may create images and ghosting which mimic left atrial thrombosis. The purpose of this study was to investigate whether a systematic approach through TEE may facilitate the recognition of LAA anatomical variants and artifacts.One hundred and sixty-four consecutive patients scheduled for cardioversion of atrial fibrillation (study population) and 30 patients (control group) undergoing mitral valve surgery were submitted to TEE using a multiplane probe in order to obtain a systematic evaluation of the LAA. The number of LAA lobes and the presence of thrombi and artifacts were evaluated.The majority of the study patients had a bilobed (53.1%) or single-lobed (34.1%) LAA. Thrombi were identified in 6%. Artifacts were found in 38 cases (23.2%) and their position was localized precisely at a distance from the transducer which was twice that from the partition-bend between the left upper pulmonary vein and left appendage, suggesting a reverberation. No differences in echocardiographic parameters were found in patients with (group 1) or without (group 2) artifacts. Cardioversion was successful in a similar percentage of cases in the two groups (group 1 68%, group 2 76%) without complications. In controls, the percentages of a single-(33%) and bilobed (40%) left appendage were similar to those found in the study population. Artifacts were identified in 11 controls (37%); no thrombi were detected during surgical left appendage inspection in these cases.A systematic approach with multiplane TEE facilitates the evaluation of the LAA anatomy and the recognition of artifacts, thus reducing the likelihood of false positive or negative diagnoses of left appendage thrombi.

Modulation of the AV node reduces the ventricular rate during AF, without affecting AV conduction during sinus rhythm. Acute and long-term results of AV node modulation in 75 patients with AF and severe related symptoms of heart failure are presented in this study. The procedure involved, in all cases, the selective ablation of the posterior inputs to the AV node; in a subgroup of 15 patients with poor modification of AV conduction properties, a sequential approach involving subsequent anterior input ablation was performed. The procedure caused acutely a prolongation of the Wenckebach cycle length (38 patients in sinus rhythm) from 334 +/- 88 to 470 +/- 80 ms (P0.01), and a reduction of the average ventricular rate (37 patients in AF) from 154 +/- 31 to 88 +/- 40 beats/min (P0.01); permanent complete AV block was induced in 9 of 75 patients (12%). Considering the "sequential" approach, an increase of the Wenckebach cycle length from 362 +/- 50 to 530 +/- 45 ms (P0.01) and a reduction of the average heart rate in patients with AF from 158 +/- 16 to 81 +/- 20 beats/min (P0.01) was obtained in this subgroup of patients, in whom the AH interval prolonged from 93 +/- 12 to 175 +/- 27 ms, and no complete AV block was observed. At a mean follow-up of 23 +/- 9 months (range 2-48), the mean number of hospital admissions per patient per year decreased from 4.2 to 0.2. Five of 49 patients with paroxysmal AF and 3 of 26 patients with chronic AF had high rate recurrences (1120 beats/min) that caused severe palpitations; these patients were considered as late clinical failures (8/75; 11%). All patients reported a substantial subjective improvement and an increased exercise tolerance, as documented by a semiquantitative questionnaire. There were no episodes of late AV block or sudden cardiac deaths. In conclusion, modulation of the AV node--either by slow pathway ablation, or by a "sequential" posterior and anterior approach in refractory patients--allows a long-term control of the ventricular rate and prevents the recurrence of severe clinical symptoms in more than 75% of patients with drug refractory AF.

We describe a rare case of intermittent dysfunction of a bileaflet mechanical aortic valve prosthesis. Subvalvular pannus overgrowth on the inflow aspect of the prosthesis impeded normal closure of one leaflet causing severe aortic regurgitation, which occurred intermittently. The complementary role of transthoracic and transesophageal echocardiography and cine-fluoroscopy in the diagnosis of this case is described.

In this study, we tested the hypothesis that hypoxic pulmonary vasoconstriction may be enhanced in systemic hypertension. The hypothesis took origin from the following two considerations: alveolar hypoxia constricts the pulmonary vessels by enhancing the Ca2+ penetration across sarcolemma of the smooth muscle cells and systemic high blood pressure is associated with an elevation of tone and reactivity of the lung vessels, which seems to depend on an excessive cytosol free Ca2+ concentration due to alterations in sodium handling and in the Na+-Ca2+ exchange system. These considerations suggest the possibility that the disorders in the biochemistry of smooth muscle contraction in hypertension facilitate the rise of cytosol Ca2+ concentration during alveolar hypoxia, thus resulting in a potentiation of the vasoconstrictor properties of this stimulus. In 43 hypertensive and 17 normotensive men, pulmonary arteriolar resistance has been evaluated during air respiration and after 15 minutes of breathing 17%, 15%, and 12% oxygen in nitrogen. Curves relating changes in pulmonary arteriolar resistance to oxygen breathing contents had similar configuration in the two populations but in hypertension were steeper and significantly shifted to the left, reflecting a lower threshold and an enhanced reactivity. This pattern was not related to differences in severity of the hypoxic stimulus, plasma catecholamine concentration, or hypocapnia and respiratory alkalosis induced by hypoxia and probably was not mediated through alpha-receptor activation. Calcium channel blockade with nifedipine was able to almost abolish both the normotensive and the hypertensive pulmonary vasoconstriction reaction. These findings support the hypothesis that hypoxic pulmonary vasoconstriction may be enhanced in systemic hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

We evaluated in patients suffering from COPD-related pulmonary hypertension whether nifedipine therapy lowers acutely and chronically pulmonary vascular pressure and resistance and whether pulmonary transmural pressure may be further lowered by the combined use of nifedipine and oxygen. Changes of the pulmonary vascular tone were determined on the pulmonary driving pressure/flow curve, which was generated by upright exercise. Fifteen patients with COPD and mean pulmonary pressure greater than or equal to 20 mm Hg were studied at control (Week 0) and after 1 wk of nifedipine treatment (180 mg daily, Week 1). It was possible to pursue the same nifedipine daily dosage for 2 months in 10 patients, who were re-evaluated after 8 wk of treatment and after nifedipine withdrawal the following week. At Week 1, mean pulmonary transmural pressure was reduced (32.8 +/- 4.1 versus 27.3 +/- 2.8 mm Hg, mean +/- SE, p less than 0.05) via active pulmonary vasodilation because the pulmonary driving pressure/flow curve was shifted right and downward. Both mean transmural pulmonary pressure lowering effect and active pulmonary vasodilatation regressed during long-term nifedipine treatment. Oxygen reduced pulmonary transmural pressure (32.8 +/- 4.1 versus 28.6 +/- 2.9 mm Hg, p less than 0.05, Week 0); however, this effect always disappeared during nifedipine treatment. We conclude that nifedipine should not be used as long-term treatment for COPD-related pulmonary hypertension and that nifedipine inhibits the oxygen capability to reduce pulmonary pressure.

The human TRIP-1 (transforming growth factor-beta (TGBbeta)-receptor interacting protein-1) cDNA encodes a protein able to associate specifically with the type II TGFbeta receptor. It is phosphorylated on serine and threonine by this receptor kinase which makes it a strong candidate as part of the TGFbeta signal transduction pathway. We have isolated the genomic sequence of TRIP-1 and found that the complete coding region is organised into 11 exons ranging from 39 to 397 bp and spanning approximately 9 kb of genomic DNA. The 5' flanking region lacks a TATA box but is GC-rich, suggesting that it is a constitutively expressed gene which is in agreement with its wide pattern of expression. Fluorescence in situ hybridisation mapped the TRIP-1 gene to chromosome 1p34.1 whereas a pseudogene is located on chromosome 7q32.

Nifedipine (10 mg qid) and captopril (25 mg qid) were tested alone and in combination in 14 patients suffering from severe primary hypertension. Each study period was of 1 week's duration. Circulatory response was evaluated through hourly pressure and pulse rate readings. The fall in pressure after oral nifedipine was maximal within 1 hr or less and was generally accompanied by palpitation and increase in pulse rate; with a six hourly dosing regimen the tendency of blood pressure to recover after each dose was interrupted by the next dose, so that values remained significantly reduced throughout the 24 hr, although pressure fluctuations were evident. Promptness of the antihypertensive action of captopril was similar, but the magnitude and the duration of the fall in pressure were less pronounced. When the converting-enzyme inhibitor was combined with the calcium-channel blocker, pressure fluctuations were not abolished, but the antihypertensive response was definitely enhanced, so that normal blood pressure was maintained for several hours during the day. Additional positive effects of captopril were mitigation of the heart rate reaction and prevention of the ankle pitting or edema elicited by nifedipine. A balance in arteriolar and venular dilatation promoted by captopril is the suggested mechanism for these effects. With the two-drug combination the function of the left ventricle was not reduced and possibly improved; blood urea nitrogen and serum electrolyte and creatinine concentration were not affected. Plasma renin activity increased with captopril and reverted toward baseline with the addition of nifedipine, suggesting an interference of the calcium-channel blocker with the release of renin.

Excessive vascular tone and overresponsiveness to adrenergic stimuli char acterize the hemodynamics of the greater and the lesser circulation in hyperten sion. We tested whether calcium entry blockade with verapamil (11 cases) or nifedipine (11 cases) may improve the vascular regulation in high blood pres sure. Mental arithmetic and cold were used as adrenergic activators. The former stimulus produced obvious elevation of epinephrine plasma concentra tion, increase of cardiac output (CO), slight systemic vasodilatation, pulmonary vasoconstriction, and rise of blood pressure in both circuits. After calcium an tagonists, the epinephrine reaction to the arithmetic test was significantly attenuated, variations in CO and systemic blood pressure were unchanged, pul monary vasoconstriction was abolished, and the pressure rise in the lesser cir cuit was halved. The cold pressor test increased norepinephrine plasma concen tration (NE pc), systemic and pulmonary blood pressure, and vascular resist ance and did not alter CO. The attained NE pc during cold was unvaried after verapamil and significantly enhanced after nifedipine; pressure and resistance responses of the two circuits were almost unchanged after the former, whereas systemic and pulmonary vascular resistance rises were importantly attenuated after the latter compound, resulting in much lower pressure reactivity. A modulation of the sympathoadrenal reaction, per se, can explain changes in the systemic and in the pulmonary vasomotion with calcium blockade during arithmetic. It would seem that after verapamil the sympathetic system was still activated during cold to such an extent as to maintain the same vasoconstrictor potency. NE pc suggests that the sympathetic discharge was not reduced by nifedipine. The impressive attenuation of the constrictor reaction in the two circuits would imply the existence of a shared vascular disorder in which cal cium ions are involved, which is more sensitive to nifedipine.

1. In systemic hypertension the pulmonary vessels show an excessive tone at rest and hyper-react to adrenoceptor stimulation. Alterations in Ca2+ handling by the vascular smooth muscle cells seem to underlie these disorders. Alveolar hypoxia also constricts pulmonary arteries, increasing the intracellular Ca2+ availability for smooth muscle contraction. This suggests the hypothesis that hypoxic pulmonary vasoconstriction depends on similar biochemical disorders, and that the response to the hypoxic stimulus may be emphasized in high blood pressure. 2. In 21 hypertensive and 10 normotensive men, pulmonary arterial pressure and arteriolar resistance have been evaluated during air respiration and after 15 min of breathing 17, 15 and 12% oxygen in nitrogen. Curves relating changes in pulmonary arterial pressure and arteriolar resistance to the oxygen content of inspired gas had a similar configuration in the two populations, but in hypertension were steeper and significantly shifted to the left of those in normotension, reflecting a lower threshold and an enhanced vasoconstrictor reactivity. 3. This pattern was not related to differences in severity of the hypoxic stimulus, degree of hypocapnia and respiratory alkalosis induced by hypoxia, and plasma catecholamines. 4. The association of high blood pressure with enhanced pulmonary vasoreactivity to alveolar hypoxia could have clinical implications in patients who are chronically hypoxic and have systemic hypertension.

Pulmonary pressure and arteriolar resistance are elevated in uncomplicated primary systemic hypertension. This study was carried out in 16 men with this form of hypertension and in 9 healthy men to compare 1) their pulmonary vascular reactivity to endogenous catecholamines released during mental arithmetic and cold pressor tests, and 2) the dose-response relation to exogenous epinephrine and norepinephrine. Arithmetic and cold pressor tests were associated, respectively, with a predominant increase in plasma epinephrine and norepinephrine concentration; changes were significantly greater in hypertensive men. During the two tests, pulmonary arteriolar resistance in the normotensive group was reduced by 13% and augmented by 7% of baseline, respectively, whereas it was raised by 31 and 70%, respectively, in the hypertensive group. In normal subjects, the dose (microgram)-response (delta dynes) relation to epinephrine was 1 = -4, 2 = -9, 3 = -9 and 4 = -10; to norepinephrine it was 2 = +3, 4 = +6, 6 = +7 and 8 = +7. In hypertensive patients, the respective relations were 1 = +18, 2 = +44, 3 = +59 and 4 = +77; and 2 = +39, 4 = +54, 6 = +76 and 8 = +98. Group differences were highly significant. In each of these circumstances, the driving pressure across the lungs was significantly augmented in the hypertensive but not the normotensive group. Both epinephrine and norepinephrine have a vasoconstrictor influence on the lesser circulation as a consequence of vascular overreactivity. The opposite changes in resistance between normotensive and hypertensive subjects produced by epinephrine suggest that a constrictor vascular supersensitivity becomes active in the pulmonary circuit with the development of systemic high blood pressure.

This study was undertaken to test whether the emphasized systemic vasomotion during sympathetic activation in hypertension is shared by the pulmonary circulation. To this end, 10 normotensive and 29 primary hypertensive subjects were investigated during adrenergic stimulation by mental arithmetic and cold pressor test. Both stimuli induced a systemic pressor reaction in both groups, which was mediated through an increase in cardiac output and a mild reduction in vascular resistance during arithmetic and through a predominant rise in systemic vascular resistance during cold. Each of these changes was emphasized in the hypertensive population as compared with the normotensive one. Pressure in the pulmonary artery remained unchanged during cold and was slightly raised (systolic) during arithmetic in normotensive subjects. On the contrary, in hypertensive subjects systolic and diastolic pulmonary pressures were consistently augmented by both stimuli, and pulmonary arteriolar resistance (dyn sec cm-5) rose from 92 in the baseline to 125 (p less than 0.01) during arithmetic and to 124 (p less than 0.01) during the cold test. This reaction is interpreted as reflecting a neurally mediated vasoconstriction and not as the consequence of mechanical or chemical changes, since no difference was observed in pulmonary wedge pressure, pleural pressure, arterial blood gas levels, and pH between controls and hypertensive subjects in the steady state and during either stressful stimulation. Baseline pulmonary arteriolar resistance was also found to correlate positively with systemic vascular resistance in the hypertensive group. When pressure changes occurred, the time course was similar in the two circuits; resistance increased to a proportionally similar degree in the two districts during the cold stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)