Search PubMed⌕ Search

Biomedical subjects

G Barletta

Publications and source records attributed to G Barletta.

71 records · Page 4Linked to original sources
PubMed1989

[Analysis of the shape of the left ventricle by studying the regional curvature and power spectrum. I. Methodology and results in normal subjects].

Quantitative analysis of left ventricular shape, obtained by measuring the regional curvatures and power spectrum of the harmonics of left ventricular outlines, is a useful method that has seldom been used in clinical research because of the need for a reliable and replicable method. The curvature of each point of an outline is the reciprocal of the radius of the circle that best fits a segment of the arc (window) centred at any specified point. We proposed a method based on the rate of change of the tangent vector with respect to the change in arc length, normalized for the width of the considered segment (Frenet-Serret formula). The series of curvature values allows us to obtain the power spectrum by means of Fourier analysis. The application of the method to a series of ellipses with variable eccentricity and size demonstrated that the width of the window is critical in the circulation of the curvature, and the choice of the number of points for computing has to be optimized to obtain the best signal-noise ratio. The method, applied using a sampling every 0.1 mm and optimized using a window of 25 points in the experimental model, is independent of the size of the samples, is able to distinguish small variations of eccentricity and to separate the signal from the noise due to digitizing and computing up to the 12th harmonic. The method has been applied to the left ventricular outlines of 16 subjects without any cardiac abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1989

[Analysis of the shape of the left ventricle by studying the regional curvature and power spectrum. II. Morphologic changes in post-infarction ischemic heart disease].

The quantitative analysis of left ventricular shape in ischaemic heart disease has seldom been performed because of the lack of a reliable and reproducible method of analysis. Diastolic and systolic left ventricular outlines in two groups of patients with previous myocardial infarction (anterior in 13 cases and inferior in 14 cases) were studied by analyzing the regional curvature and the power spectrum. This method allowed us to obtain left ventricular curvatures from the mitral to the aortic corner and the power spectrum of the first 12 harmonics. The results obtained in these two groups were compared with those obtained in 16 normal subjects. The diastolic power spectrum in both infarcted groups was similar. It was characterized by a double peak which was different from that of the normal subjects. Slight differences between the two infarcted groups were due to the diverse amplitude of the highest harmonics. The regional analysis of the curvature in both groups showed similar abnormalities of the posterobasal, inferior and antero-basal regions. The posterior wall showed a uniform curvature with the point of minimum shifted towards the mitral corner; the anterior wall showed a rounded profile with a regular curvature. In the group with anterior myocardial infarction the curvature of the inferior wall was negative, i.e., convex towards the left ventricular cavity. The systolic power spectrum showed a double peak profile which was different from that of the normal subjects. There were some differences between the two groups as regards the first and the highest degree harmonics. In inferior myocardial infarction the apex was rounded whereas in the anterior one the most important abnormalities were the convexity of the inferior wall towards the inside and the presence of a region with minor curvature between two regions with greater curvature of the anterior wall. Some of the systolic abnormalities involved the probable site of the infarct while others were in remote regions. The meaning of remote abnormalities is not clear. However, we did not verify a correlation between wall motion, at least as shortening of radii, and regional curvature. The abnormalities of the diastolic outline were independent of the site of the infarct and did not appear to be correlated to end-diastolic pressure or to the ejection fraction. They seemed to be the morphological counterpart of the filling abnormalities reported in ischaemic cardiac disease and they may depend on the regional distribution of stresses.

Cineradiography↗
PubMed1988

[Aneurysms of the left sinus of Valsalva].

The acquired aneurysm of the left aortic sinus is a rare lesion. We observed two cases: the former ruptured in the left ventricle, the latter in the right ventricle. Both cases were identified by echocardiographic examination. The diagnosis was confirmed by the cardiac catheterization and aortography and then at cardiac surgery. In the latter case the diagnosis of rupture was done using Doppler technique. Our experience indicates that, at least in selected cases, the diagnosis of aneurysm of Valsalva sinus and that of rupture are possible by means of two-dimensional and Doppler echocardiography.

Adult↗
PubMed1983

Regional left ventricular wall motion abnormalities in chronic volume overload.

Computer-assisted analysis of left ventricular (LV) wall motion has been performed in 12 patients (pts) with chronic volume overload and in seven normal subjects. All pts were in sinus rhythm, without congestive heart failure and without coronary artery disease at selective coronary angiography; 30 degrees right anterior oblique ventriculograms were employed in each case. Thirty-six radiants were automatically traced and the percent shortening of each radiant was calculated using two different reference methods (fix and floating methods). In valvular heart disease (VHD) pts LV volumes were significantly increased, and ejection fraction and LV eccentricity were significantly reduced. LV eccentricity inversely correlated with LV volumes. VHD pts showed regional LV abnormalities. Inferoapical and anterior wall motion was significantly reduced (two-sample t-test P less than 0.05) using the fix method. With this method a significant inverse correlation between percent shortening of the radiants correspondent to the inferoapical region and end-diastolic and end-systolic volumes was found; a significant direct correlation was found with LV systolic eccentricity. Ejection fraction directly correlated with the percent shortening of radiants correspondent to both the anterior and inferior regions. The role of LV "dynamic geometry" alterations as a possible cause for the observed regional LV wall motion abnormalities is emphasized.

Adult↗
PubMed1983

Echocardiographic evidence of increased mitral-aortic separation in discrete subaortic stenosis.

The present study reports the two-dimensional echocardiographic pattern of 6 patients affected by discrete subaortic stenosis. The diagnosis was proven at cardiac catheterization. The echocardiographic picture was characterized by a deformity of the left ventricular outflow tract due to an inward-protruding upper septum and to an elongated and domed mitral-aortic separation. The latter finding has been described in anatomic studies but has never been reported with wide-angle echocardiography.

Adolescent↗
PubMed1982

Effect of dextran infusion on left atrial size in normal subjects.

The purpose of this study was to evaluate left atrium dimension during acute volume loading. Low molecular weight dextran solution (1,000 ml) was continuously infused in 10 subjects without cardiac disease. Measurements of pulmonary arterial, capillary wedge, right atrial and systemic blood pressures, cardiac output, heart rate and M-mode left atrial maximum diameter were made in basal conditions and after 250, 500, 750 and 1,000 ml of dextran. In 4 subjects a two-dimensional echocardiogram was also obtained in the short axis and four-chamber views. Dextran produced the following changes (mean values +/- standard deviation) in haemodynamic variables: right atrial and wedge pressures increased from 3.2 +/- 1.55 to 12.3 +/- 3.08 mm Hg (p less than 0.001) and from 6.9 +/- 1.45 to 20.6 +/- 3.44 mm Hg (p less than 0.001), respectively. Stroke volume increased from 70.5 +/- 31.6 to 86.6 +/- 24.6 ml/beat (p less than 0.05). Heart rate increased from 81.0 +/- 15.8 to 95.0 +/- 12.3 beats/min (p less than 0.05). Left atrial maximum diameter showed a slight increase after 500 ml of dextran (from 39.5 +/- 4.1 to 43.6 +/- 5.0 mm, p less than 0.05). It did not further increase by continuing the infusion up to 1,000 ml despite the marked increase in wedge pressure. The results show that left atrial size is partly independent of haemodynamic changes and that the compliance of the left atrium is relatively low. This finding is consistent with the common clinical observation that the left atrium is only slightly enlarged in acute mitral insufficiency.

Adult↗
PubMed1982

Pheochromocytoma presenting as possible cardiomyopathy.

A case of pheochromocytoma presenting as a possible hypertrophic obstructive cardiomyopathy is reported. In a 67 years old woman without previous history of hypertension, the echocardiogram showed left ventricular concentric hypertrophy and systolic anterior movement of the mitral valve. The carotid pulse was deformed with a spike-and-dome pattern. The complex interactions between myocardial adrenergic receptors sites and catecholamines, and the relation between these substances and the pattern of cardiac hypertrophy are discussed.

Adrenal Gland Neoplasms↗
PubMed1982

[Observations on prolapse of the aortic cusps].

The patterns of valve motion were analyzed in 14 patients with combined aortic and mitral valve prolapse by two-dimensional echocardiography. Four patients have also tricuspid valve prolapse. In one we could find evidence of a myxomatous pulmonic valve with prolapse of the posterior cusp. By two-dimensional echocardiography all patients had redundant aortic leaflets bulging into left ventricular outflow tract during diastole. M-mode examination of the aorta was normal in five patients; eccentricity of the diastolic aortic valve echo was found in two patients; seven showed multiple echoes from the valve leaflets, with diastolic fluttering. The aortic valve was visualized in the left ventricular outflow tract during diastole in one patient. The size of the aortic root was normal in all. Six patients had transient ischemic cerebral attacks and no evidence of extracranial or intracranial vascular disease by angiography. As polyvalvular prolapse as demonstrated by echo suggest a myxomatous degeneration of the valves, we hypothesize that there may be a causal relationship between TIA and this type of pathological process.

Adolescent↗
PubMed1980

[Cineangiographic and hemodynamic evaluation of left bundle branch block].

Left cardiac catheterisation, selective coronarography and ventriculography were employed in a study of 89 patients with left bundle-branch block. Three subjects presented normal haemodynamic and cineangiographic data, 16 displayed valve defects, usually of the aorta, 34 had ischaemic heart disease, and 36 cardiomyopathy mostly of a congestive type. Deviation of the axis in excess of--30 degrees on the frontal plane appeared to be more frequently accompanied by ischaemia, though this finding was not prognostic from the haemodynamic standpoint. A prolonged QRS (over 0.15") was more frequent in valvular heart disease and accompanied by more evident left valve dysfunction. Comparison between the 34 ischaemic patients and 317 coronary patients without left bundle-branch block showed that the former has a higher frequency of leftness in the distribution of their coronary circulation, and more extensive impairment of the coronary arteries, especially the ramus interventricularis anterior. Changes in left ventricle kinetics and serious hypokinesia and/or akinesia appear to be due to the heart disease responsible of the block. The series examined did not make it clear whether this intraventricular conduction defect can cause albeit slight alterations in left ventricle wall motility.

Adult↗
PubMed1980

Separation and characterization of NAD- and NADP-specific succinate-semialdehyde dehydrogenase from Escherichia coli K-12 3300.

Two distinct proteins endowed with succinate-semialdehyde dehydrogenase (succinate-semialdehyde:NAD(P)+oxidoreductase, EC 1.2.1.16) activity were separated and partially purified by ammonium sulphate fractionation or Sephadex G-200 gel-filtration or both. They differ by coenzyme specificity (NAD or NADP), molecular weight, temperature and pH resistance, pH-activity curves, beta-mercaptoethanol activation. Moreover, the NADP-specific enzyme catalyzes only the oxidation of succinate-semialdehyde among a number of aldehydes tested, whereas the NAD-specific form is active also towards n-butyraldehyde. The Km for the substrate is also appreciably different according to the coenzyme specificity, while the Km values for NAD and NADP are quite similar. Finally, the growth of the cells on gamma-aminobutyrate as the sole source of nitrogen resulted in enhanced level of the NAD-dependent succinate-semialdehyde dehydrogenase, with concurrent decrease of the alternate enzyme activity. On the basis of the above results, distinct metabolic roles are suggested for the two enzymes forms.

Aldehyde Oxidoreductases↗