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Semplice algoritmo per la valutazione del rilasciamento isovolumetrico del ventricolo sinistro.
No full textDynamic right and left ventricular interaction in tne rabbit: simultaneous measurements of ventricular pressure-volume loops.
No full textPURPOSE: This study was performed to characterize the dynamic factors determining ventricular interdependence in an open-pericardium intact animal model. MATERIALS AND METHODS: Simultaneous measures of right ventricular (RV) and left ventricular (LV) pressures and volumes in 6 urethane-anesthetized open-chested, open-pericardium rabbits. RV and LV V were calculated every 2 milliseconds. Measurements were made at initial baseline blood volume, and again after two infusions of 20 mL/kg isoconductive colloid solution. At each blood volume level, partial aortic (AO), pulmonary artery (PAO), and inferior vena caval (IVC) occlusions were performed. Biventricular diastolic compliance and end-systolic elastance were calculated from these data. RESULTS: Baseline end-diastolic (ED) and end-systolic (ES) V were 3.29 +/- 0.55 and 2.43 +/- 0.33 mL (mean +/- SD) for the LV, and 3.38 +/- 1.56 and 2.84 +/- 1.36 mL for the RV, respectively. AO increased all LV pressure and volume (P < .05) but did not alter RV ED volume (2.85 +/- 1.20 mL) or ED pressure (3.3 +/- 2.0 to 3.6 +/- 2.1 mm Hg). PAO increased RV ES pressure (P < .05) but did not alter RV ED volume, ED pressure, or ES volume, although it decreased LV ED volume (2.82 +/- 0.59, P < .05). AO also immediately increased end-systolic RV elastance to a value greater than that defined by IVC (7.9 +/- 4.4 to 10.9 +/- 6.6 mm Hg/mL, P < .05). Intravascular volume expansion though increasing baseline pressure and volume, did not alter qualitatively biventricular responses to AO, PA, or IVC. CONCLUSION: Ventricular interdependence has both systolic and diastolic components that have differing directional effects. In the pericardectomized rabbit, increases in RV ED volume decrease LV ED volume by decreasing LV diastolic compliance, but do not alter LV systolic function. Whereas, increases in LV ED volume decrease RV ES volume resulting in an increase in RV maximal elastance, but minimally alter RV diastolic function
Durante occlusione coronarica sperimentale la dobutamina rallenta ulteriormente la costante di tempo del rilasciamento isovolumetrico.
No full textAlthough end-systolic pressure-length relationship (ESPLR) is now widely used as a regional substitute for the end-systolic pressure-volume relationship, there are some reservations about its use as an index of systolic performance. This study aimed at assessing whether by using end-ejection (zero aortic flow) as a definition of end-systole, ESPLR can be used to characterize myocardial performance independent of load, and if the choice of the region where to implant the sonomicrometers is critical. Ten anaesthetized dogs (16 +/- 2 kg) were instrumented with a left ventricular (LV) pressure micromanometer and an aortic flow probe. Sonomicrometers were implanted in the apical (L1) and the mid-ventricular (L2) regions of the anterior LV wall, and in the basal region of the lateral wall (L3). End-systolic pressure-length relationships were obtained during acute preload reduction induced by the inflation of a vena caval balloon. This evaluation was repeated after increasing end-diastolic pressure to 14-18 mmHg (delta PL), after increasing systolic pressure by 15 (delta P-I) and 25 mmHg (delta P-II) with graded descending aorta occlusion, and during dobutamine infusions at 2.5 (Db 2.5) and 5 micrograms/kg/min (Db5). End-systolic pressure-length relationships (r > 0.97; pressure range: 70-100 mmHg) were characterized by their slopes (Ees), the extrapolated intercept at zero pressure (L0) and the values of segment length at a pressure of 75 (L75) and 100 mmHg (L100). In all the myocardial regions studied by sonomicrometry, the increments in preload and afterload did not significantly shift ESPLR
Vitamin D deficiency is associated with impaired reperfusion in STEMI patients undergoing primary percutaneous coronary intervention
No full textBackground and aims: Vitamin D displays a broad spectrum of cardioprotective effects, preventing oxidative stress, inflammation and thrombosis and improving endothelial function. Previous studies have associated vitamin D deficiency with more extended and severe coronary artery disease (CAD) and worse outcome, and especially among patients with ST-segment elevation myocardial infarction (STEMI). However, few data have been reported on the association of vitamin D levels with the angiographic findings and epicardial reperfusion in STEMI patients undergoing primary percutaneous coronary intervention (pPCI), that was therefore the aim of the present study. Methods and results: A consecutive cohort of patients admitted for STEMI and treated with pPCI were included. The levels of 25(OH)D were assessed at admission by chemiluminescence immunoassay kit LIAISON® Vitamin D assay (Diasorin Inc). Hypovitaminosis D was defined for 25(OH)D < 10 ng/ml. We included in our study 450 patients, divided according to tertiles values of 25(OH)D. Lower vitamin D was associated to a higher use of diuretics (p = 0.02), higher levels of white blood cells and glycemia (p < 0.001), lower prevalence of lesions on bifurcations (p = 0.03) and smaller diameter of the target coronary vessel (p = 0.03). Procedural characteristics and pre-procedural TIMI flow were not different according to vitamin D levels, but for a higher rate of impaired epicardial reperfusion (12.8% vs 8.1% vs 5.3%, p = 0.03, adjusted OR[95%CI] = 2.6[1.05–6.6], p = 0.04 for I vs III tertile), requiring higher use of adenosine (p = 0.006) and glycoprotein IIbIIIa inhibitors (p = 0.01). Conclusion: The present study shows that among patients with STEMI undergoing pPCI, lower levels of vitamin D are independently associated with impaired reperfusion, Future dedicated studies will shed light on the prognostic implications of hypovitaminosis D in these patients and the potential therapeutic perspectives
Confronto tra apicografia calibrata e tecniche invasive della valutazione della diastole: dati preliminari.
No full textPreprocedural β-Blockers in the Functional Assessment of Intermediate Coronary Lesions by Instantaneous Wave-Free Ratio
No full textAim: Instantaneous wave-free ratio (iFR) has emerged as the strategy of choice for the assessment of intermediate coronary lesions. The impact of preprocedural β-blockers therapy on the iFR was the aim of this study. Methods: We included patients undergoing functional assessment of intermediate (40%-70%) coronary lesions in 2 centers. The iFR measurement was performed by pressure-recording guidewire and calculated at the core laboratory using the manufacturers’ dedicated software. Minimal luminal diameter, reference diameter, percent diameter stenosis, and length of the lesion were measured. Positive iFR was considered for values <0.90. Results: We included 197 patients undergoing functional evaluation of 223 coronary lesions. Patients on β-blockers (69%) had more frequently hypertension (P =.05); previous myocardial infarction (P =.01); therapy with clopidogrel (P =.02), statins, and aspirin; and acute coronary syndrome at presentation (P <.001, respectively). Mean iFR values were slightly higher in patients on β-blockers (0.94 ± 0.06 vs 0.92 ± 0.06, P =.11). The rate of positive iFR was significantly lower with β-blockers (14.9% vs 27.5%, P =.04). On multivariate analysis, β-blockers use was a predictor of the significance of coronary stenoses (odds ratio [OR] = 0.48; 95% CI = 0.23-0.98; P =.05) together with lesion length (OR = 1.04; 95% CI = 1.01-1.07; P =.007). Conclusion: Among patients undergoing iFR, preprocedural β-blockers are associated with higher absolute values and a lower rate of positive iFR
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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