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Biomedical subjects

M Baroni

Publications and source records attributed to M Baroni.

At least 19 recordsLinked to original sources
PubMed1999

Computer evaluation of left ventricular wall motion by means of shape-based tracking and symbolic description.

Relevant cardiac pathologies manifest themselves as abnormal movements of left ventricular (LV) myocardial wall. An objective quantification is usually accomplished by computer analysis of temporal sequences of LV contours, as obtained by angiography or echography. However the choice of the reference system for measuring motion is still open to discussion. Simple geometric models cannot deal with the non-uniform myocardial fibre structure, which gives rise to non-rigid movements, asynchronous even in normal subjects. Therefore, a new method, Curvature-Motion (CM), was developed for improving motion assessment. Since LV contour shape and position change smoothly throughout the cardiac cycle, the points of curvature extremes are tracked frame-to-frame and selected by exploiting physiologically-based assumptions; then, the points lying among these landmarks are mapped onto sequential contours, according to local displacements and curvature changes. In this way point-trajectories are allowed to be curvilinear and different in systole and diastole. CM gave no significant differences in estimating the known motion of computer-generated contours (R=0.88), unlike other methods commonly adopted (R<0.80). Moreover, for the evaluation of regional wall motion of a preclassified set of angiographic contours, CM showed a greater specificity (88%) and accuracy (90%) with respect to the centre-line method (respectively 83% and 87%). Finally, a fuzzy logic inference system is proposed for translating significant motion patterns from the quantitative form, as provided by the analysis method, into the linguistic terms used by cardiologists in their clinical examinations. This makes the interpretation of quantitative analysis easier and allows medical users to interact with the system for searching particular properties in a single clinical report as well as in a large database.

Algorithms↗
PubMed1999

A case of narcolepsy-cataplexy associated with distemper encephalitis.

Narcolepsy associated with localized brain lesions is described in a 10-month-old Argentine Dogo. Neurological examination and MRI study suggested an inflammatory lesion of the left frontal lobe. Postmortem examination revealed diffuse encephalitis in the forebrain and marked necrotic lesions in the ventral pontine area. Immunohistochemistry for distemper virus antigen showed positive staining of the cytoplasm of many neurones of the pons and cerebral cortex. The pathological pattern was suggestive of post-vaccinal distemper encephalitis and the localization of the lesions was consistent with the neurological syndrome shown by the animal. At any event, the possibility of coincidental findings of distemper encephalitis and idiopathic narcolepsy must be accounted for.

Animals↗
PubMed1999

Effects of reconstructive surgery for left ventricular anterior aneurysm on ventriculoarterial coupling.

OBJECTIVE: To investigate left ventricular elastance (Emax) and effective arterial elastance (Ea) in postinfarction left ventricular aneurysm and evaluate their role in left ventricular function improvement after endoventricular circular patch plasty (EVCPP). Ventriculoarterial coupling has never been studied in these patients. PATIENTS: 22 consecutive patients (49 to 73 years) with left ventricular anterior aneurysm. METHODS: Haemodynamic studies were done before and two weeks after EVCPP. Ventriculography was performed during atrial pacing (100 beats/min). Pressure/volume loops were analysed and derived parameters measured. Emax was estimated by applying the "single beat" method. Ea was calculated as end systolic pressure/stroke volume. RESULTS: Left ventricular volumes and Ea decreased after surgery: end diastolic volume index from mean (SD) 155 (53) to 106 (29); end systolic volume index from 112 (51) to 62 (30) ml/m2 (both p < 0.0001); Ea from 1.65 (0.70) to 1.39 (0.41) mm Hg/ml (p = 0.04). Ejection fraction and Emax increased, without significant changes in stroke volume and work. The decrease in Ea was directly correlated with its preoperative value. The time interval between left ventricular pressure upstroke and peak systolic pressure decreased, from 237 (39) to 191 (41) ms (p < 0.0001), paralleling morphological changes in pressure tracings. CONCLUSIONS: After EVCPP, ventriculoarterial coupling improves because of the fall in Ea caused by end systolic pressure reduction. The improvement is related to aortic pressure waveform changes and improved relaxation.

Aged↗
PubMed1998

Acute hemodynamic effects of endogenous adenosine in patients with chronic heart failure.

OBJECTIVE: The objective of this study was to assess the acute hemodynamic effects of endogenous adenosine accumulation in patients with chronic heart failure. Exogenously administered adenosine has been shown to reduce pulmonary vascular resistance and to increase cardiac index in normal subjects and in patients with pulmonary hypertension or end-stage biventricular heart failure. Endogenous adenosine accumulation can be provoked by dipyridamole. METHODS AND RESULTS: Ultra-low-dose dipyridamole (0.07 mg/kg/min for 4 minutes) was administered in 20 patients with either symptomatic idiopathic (n = 12) or ischemic (n = 8) dilated cardiomyopathy and reduced left ventricular ejection fraction (mean 25%+/-5%). Hemodynamic variables were measured before and within 1 minute from the end of dipyridamole infusion. After dipyridamole administration, a mild but significant increase in heart rate (4.5%; p = 0.03) and reduction in mean blood pressure (6.8%; p < 0.001) without changes in right atrial pressure (p = NS) were detected. Dipyridamole increased cardiac output by 26.6% (p < 0.001), cardiac index by 24% (p < 0.001), and stroke volume by 19.8% (p < 0.001), with concomitant 24.6% reduction of systemic vascular resistance (p < 0.001). Moreover, dipyridamole reduced mean pulmonary artery pressure by 8.3% (p < 0.01) and pulmonary vascular resistance by 33.3% (p = 0.001), without changes in pulmonary wedge pressure (p = NS). A significant correlation between percent decrease from baseline in pulmonary and systemic vascular resistance (r = 0.66; p = 0.002) was found after administration of dipyridamole. CONCLUSIONS: Endogenous adenosine accumulation induced by ultra-low-dose dipyridamole infusion acutely improves the hemodynamic profile, decreasing pulmonary and, to a lower extent, systemic vascular resistance and increasing cardiac index in patients with severe chronic heart failure.

Adenosine↗
PubMed1998

Preoperative assessment of coronary artery disease in aortic stenosis: a dipyridamole echocardiographic study.

BACKGROUND: The aim of this study was to establish the feasibility, safety, and diagnostic accuracy of the dipyridamole echocardiography test in patients with severe aortic valve stenosis for noninvasive detection of coexisting coronary artery disease. METHODS: The high-dose dipyridamole echocardiography test was performed in 52 patients with severe aortic stenosis; all patients also underwent coronary angiography, independent of test results, before cardiac operation. RESULTS: The dipyridamole echocardiography test was completed without major complications. One patient had transient atrial fibrillation that was reversed by aminophylline. Thirty-one patients (60%) had a negative test result; all had normal coronary arteries. Ten of the 21 patients (48%) with a positive test result had coexisting coronary artery disease. The positive predictive value of the dipyridamole echocardiography test for detection of coronary disease in patients with severe aortic stenosis was 48%. The negative predictive value was 100%. The sensitivity was 100% and the specificity was 74%. CONCLUSIONS: Dipyridamole echocardiography is a safe and feasible tool in patients with severe aortic stenosis eligible for a cardiac operation. A negative test result reliably rules out a significant stenosis, whereas a positive one is much less accurate in predicting coronary artery disease.

Aortic Valve Stenosis↗
PubMed1998

Regional and temporal nonuniformity of shape and wall movement in the normal left ventricle.

Asymmetry of left ventricular (LV) shape and asynchrony of regional LV movement have been described in the normal human heart, but never correlated to each other. In 16 normal subjects, right anterior oblique ventriculography was used to obtain volumes, regional wall motion (centerline method) and curvature (windowed Fourier series approximation of contours) over the entire cardiac cycle. The apex had the greatest curvature, while the posterior wall had a negative end-diastolic curvature that decreased further at early-systole and became positive at end-systole. The anterior region had the greatest and the anteroapical region the least fractional shortening. Asynchrony was evident as a delayed contraction of the infero- and anteroapical regions, and as a greater rate of late-systolic shortening of the anterior wall than that of the apex. Shape changes and shortening were dyssynchronous in the apical regions where the greatest changes occurred at early diastole. Temporal and regional nonuniformity of shape and movement exists in normal subjects. Dyssynchrony between shape and regional contraction of the apical regions deserves further studies.

Adult↗
PubMed1997

Dipyridamole stress echocardiography: state of the art 1996. EPIC (Echo Persantin International Cooperative) Study Group.

Dipyridamole stress is the forerunner and prototype of pharmacological stress echo tests in the diagnosis of coronary artery disease. Among the various stress echo tests, it is probably the least technically demanding to perform and the easiest to interpret. Its accuracy is similar to dobutamine stress echocardiography but its feasibility is higher. The prognostic impact of dipyridamole stress echo has also been proven for presentation of hard end-points such as cardiac death. The safety and prognostic value of this test has been conclusively demonstrated as a result of extensive experience in large scale multicentre projects. Dipyridamole stress is many different tests in one: dipyridamole atropine is best for diagnosis; dipyridamole dobutamine or dipyridamole-exercise is highly sensitive for the detection of minor forms of coronary artery disease; low and high dose dipyridamole is best suited for prognostic stratification; infra-low dipyridamole with low dose dobutamine administration is probably best suited for selective myocardial viability identification. Each patient should have their own test, tailored on the basis of the clinical picture and the diagnostic issue.

Coronary Disease↗
PubMed1997

The relative value of exercise-electrocardiography and dipyridamole stress echocardiography for risk stratification early after uncomplicated myocardial infarction. The EPIC (Echo Persantine International Cooperative) Study Group.

BACKGROUND: Rational prognostic algorithm should be developed considering the logical progression of the information as it becomes available to the physician, with clinical data first, ECG data second and stress imaging data last. The aim of the present study was to assess in a clinically realistic fashion the relative prognostic value of exercise electrocardiography test (EET) and dipyridamole-echocardiography test (DET) early after first acute uncomplicated myocardial infarction. METHODS AND RESULTS: Five hundred and forty-seven in-hospital patients (age = 56 +/- 9 years) with recent clinically uncomplicated first myocardial infarction, baseline echocardiographic findings of satisfactory quality, interpretable ECG and capability to exercise underwent a resting 2D echocardiogram, a DET and an EET at a mean of 10 days from the infarction and were followed up for 16.2 +/- 11 months. During the follow-up, there were 17 cardiac deaths, 19 non-fatal myocardial infarctions and 49 unstable angina. When cardiac death was considered as the only significant event, with multivariate analysis, peak dipyridamole Wall Motion Score Index was the only significant predictor (chi 2 = 5.66; p = 0.013; relative risk estimate = 4.7; confidence intervals = 1.35-16.08). In presence of a negative exercise electrocardiography test for both chest pain and electrocardiographic criteria, the death rate was 2%. CONCLUSION: DET provides stronger information in comparison with historical and EET variables. However, a negative maximal EET is sufficient to identify a very low risk subset in whom additional testing may not be warranted.

Cause of Death↗
PubMed1997

Glucose transporters (GLUT 1, GLUT 3) mRNA in human placenta of diabetic and non-diabetic pregnancies.

Glucose transporters (GLUT) catalyse the transport of glucose in many human tissues, including the placenta. On the other hand glucose concentrations can affect both glucose transport activity and level of GLUT mRNA and protein. Up to now very few studies, concerning GLUT in the placenta appeared and studies in vivo in human diabetic pregnancy are lacking. Therefore we investigated placental GLUT 1 and GLUT 3 mRNA in 10 diabetic (5 IDDM, 2 NIDDM, 3 GDM) and 9 non-diabetic women. GLUT 1 mRNA was found significantly correlated with maternal age (> 30 vs < 30 years: p < 0.025), with placental weight (> 575 vs < 575 g: p < 0.05), while GLUT 3 mRNA decreased significantly in late gestation of diabetic women (38-40 vs < 38 weeks: p < 0.025). In addition GLUT 3 was significantly lower in the diabetic than in non-diabetic women in late gestation. These preliminary results deserve to better elucidate feto-maternal carbohydrate metabolism at the placental level in normal as well as diabetic pregnancy.

Adult↗
PubMed1996

Ambulatory follow-up of aortic dissection: comparison between computed tomography and biplane transesophageal echocardiography.

UNLABELLED: Aim of the study was to assess the relative usefulness of transesophageal echocardiography (TEE) and X-ray computed tomography (CT) in the follow-up of patients who survived an aortic dissection. MATERIALS AND METHODS: We evaluated 44 patients (age = 57 +/- 12 years) with treated aortic dissection: 14 had a De Bakey type I, 20 a type II and 1 patient a type III dissection treated surgically: 1 patient had a type I, 1 a type II and 7 a type III dissection treated medically. All entered an outpatient follow-up program with serial evaluations at 1, 6 and 12 months after initial diagnosis by dual noninvasive imaging protocol. A contrast-enhanced CT scan and a TEE with biplane probe were performed on the same day and in random order. RESULTS: A total of 252 evaluations with both CT and TEE were considered. A completely normal study was found in 45 TEE and 48 CT evaluations. The following abnormal findings could be documented by one or both techniques: thrombus in the false lumen (TEE: n = 48; CT: n = 45 evaluations); intimal flap (TEE and CT: n = 68); aortic dilatation (TEE and CT: n = 15); pericardial effusion (TEE and CT: n = 3); aortic pseudoaneurysm (TEE: n = 2; CT: n = 3); isthmic coarctation (TEE and CT: n = 1). Regarding the presence or absence of these abnormalities, which are within the diagnostic domain of both imaging techniques, the results were fully concordant in 245 studies, and discordant in 7, with an overall agreement of 97%. In addition, some abnormal findings could be detected by TEE only: aortic insufficiency (n = 36); intimal tear (n = 25); spontaneous echocontrast effect in the false lumen (n = 39 evaluations). Other abnormal findings could be detected by CT only: a pleural effusion in 4, a truncus anonymous dissection in 1, a pseudoaneurysm due to suture dehiscence of the distal anastomosis of the ascending aorta in 1 evaluation (which yielded ambiguous results by TEE, with turbulent flow departing from the graft). CONCLUSION: Both CT and TEE are atraumatic, safe and accurate techniques for serial follow-up imaging of patients treated for aortic dissection. Information provided by CT is largely redundant, rather than additive, to that provided by TEE. The latter should be probably preferred for shorter imaging time, accuracy and convenience, although CT might still play a role in selected cases of ambiguous TEE results.

Adult↗
PubMed1996

Education for the nursing of children and their families: standards and guidelines for prelicensure and early professional education.

To strengthen the preparation of nurses for care of children and families, standards and guidelines for prelicensure and early professional education were developed by a working group with broad-based input. Assumptions, theory, practice, and research underlying the standards and guidelines concerned the nature of health care, knowledge, teaching, learning, and evaluation. The 11 standards are presented and guidelines are illustrated. How they are implemented will depend on local resources and philosophies. Continued dialogue among nurse educators is needed to refine and develop the standards and guidelines.

Humans↗
PubMed1996

Functional identification of rat atypical beta-adrenoceptors by the first beta 3-selective antagonists, aryloxypropanolaminotetralins.

1. We have assessed the relative abilities of compounds belonging to the new aryloxypropanolaminotetralin (APAT) class and of the reference beta-adrenoceptor-blocking agent, alprenolol, to antagonize functional responses in vitro and in vivo involving atypical (beta 3) or conventional (beta 1 and beta 2) beta-adrenoceptors. 2. The range of pA2 values for three representative APATs against inhibition of spontaneous motility in the rat isolated colon by the selective beta 3-adrenoceptor agonist, SR 58611A (8.1-8.8), was well above similarly calculated values for non-competitive antagonism of guinea-pig trachea relaxation by salbutamol (beta 2, 6.5-6.9) and the atrial chronotropic response by isoprenaline (beta 1, 6.7-7.3). Alprenolol, however, was substantially more potent in antagonizing atrial (pA2, 8.2) and tracheal (pA2, 8.9) responses than SR 58611A mediated inhibition of colonic motility (pA2, 6.8). 3. Several APAT isomers with different configurations at the chiral carbons, when tested on isolated organs, presented stringent stereochemical requirements for beta 3-selectivity, including high antagonist potency-ratios between active and inactive enantiomers. 4. In vivo, the inhibition of colonic motility and the thermogenic response of brown adipose tissue elicited in rats by the selective beta 3-adrenoceptor agonists SR 58611A and BRL 37344 respectively were substantially diminished by the representative APAT, SR 59230A, at oral doses (< or = 5 mg kg-1) well below those half maximally effective (ID50) for preventing beta 1-(isoprenaline tachycardia > or = 80 mg kg-1) or beta 2-(salbutamol bronchodilatation, 44 mg kg-1) mediated responses. Alprenolol, as expected, was a less potent and nonselective antagonist of the putative beta 3-responses. 5. These findings support APATs as the first potent, orally effective selective antagonists at beta 3-adrenoceptors, and provide final unambiguous evidence that beta 3-adrenoceptors underlie inhibition of colonic motility and brown adipose tissue thermogenesis in rats.

Adipose Tissue↗
PubMed1996

Mechanisms of regional ischaemic changes during dipyridamole echocardiography in patients with severe aortic valve stenosis and normal coronary arteries.

OBJECTIVE: Vasodilator stress echocardiography can cause myocardial ischaemia in patients with severe aortic valve stenosis and angiographically normal coronary arteries. The aim of the study was to determine the mechanism of ischaemia in this clinical model. METHODS: The study group comprised patients with severe aortic valve stenosis and normal coronary arteries: 25 patients (17 males, eight females; age 63 (SD 11) years) underwent a high dose (up to 0.84 mg/kg over 10 min) dipyridamole echocardiography test both before (2-4 d) and after (10-15 d) aortic valve replacement. Mean aortic pressure gradient was 96 (15) mm Hg, with a left ventricular mass index of 228 (49) g/m2. The dipyridamole echocardiography test was well tolerated and interpretable in all patients. RESULTS: Dipyridamole infusion induced chest pain in seven patients before and in no patient after surgery (28 v 0%, P < 0.01), ST segment depression in 12 patients before and two after surgery (48 v 8%, P < 0.01), and a transient regional dyssynergy in 10 patients before and two after surgery (40 v 8%, P < 0.01). In the preoperative evaluation, patients with an echocardiographically positive dipyridamole echocardiography test were comparable with patients with negative test as far as left ventricular mass index [240 (67) v 230 (64) g/m2, NS] and mean aortic pressure gradient [95 (22) v 92 (21) mm Hg, NS] were concerned. When compared to the preoperative assessment, the resting echo assessment in the postoperative evaluation showed unchanged values of left ventricular mass index [pre 228 (49) g/m2 v post 220 (36) g/m2, NS], but markedly decreased values of mean aortic gradient [pre 95 (15) mm Hg v post 22 (5) mm Hg, P < 0.01] and left ventricular wall stress index [pre 134 (30) g/cm2 v post 89 (19) g/cm2]. CONCLUSIONS: Dipyridamole echocardiography is a suitable clinical technique for assessing the ischaemic vulnerability of the left ventricle in severe aortic valve stenosis with angiographically normal coronary arteries. The frequent disappearance of the ischaemic response early after aortic valve replacement suggests that haemodynamic factors such as compressive diastolic wall stress or afterload reduction are important components of myocardial ischaemic vulnerability under these circumstances.

Adult↗
PubMed1996

Multimodal treatment to prevent the late whiplash syndrome.

In order to assess the long-term efficacy of a multi-modal rehabilitation approach on whiplash injury, 60 patients were recruited within two months after neck injury. They were randomly allocated either to an experimental multimodal treatment (A) consisting of postural training, manual technique and psychological support or to a control treatment (B), using physical agents only, such as electrical and sonic modalities. Pain level, range of movement, self-rating scale of treatment efficacy and return-to-work delay were evaluated before and at the end of treatment, and later, 30 and 180 days after randomisation. The benefit obtained with treatment "A" was greater and longer lasting than that experienced using "B", despite the fact that the same benefit was obtained in joint mobility in the two groups. Patients undergoing the experimental treatment returned to their usual occupations sooner than the controls. The results seem to confirm the hypothesis of a multifactorial involvement as a possible mechanism for the late whiplash syndrome.

Adolescent↗
PubMed1995

Regional myocardial performance of non-ischaemic zones remote from anterior wall left ventricular aneurysm. Effects of aneurysmectomy.

The aim of this work was to investigate the effects of resecting a post-infarction left ventricular anterior aneurysm on the kinetics of the non-ischaemic inferior wall, remote from the healed lesion. Thirteen patients, with an anterior post-infarction aneurysm and a normal right coronary artery who underwent aneurysmectomy with endoventricular circular patch plasty reconstruction, had a complete haemodynamic study before and shortly after surgery. The shape of the left ventricle was quantitatively analysed by calculating the regional curvature at 90 points of the angiographic outlines (30 degrees right anterior oblique projection). Segmental wall motion was studied by means of the centreline method and by constructing pressure-length loops from the endocardial movement of 18 chords intersecting the left ventricular inferior contour and by simultaneously tracing the high-fidelity left ventricular pressure. Analysis of pressure-length regional loops showed a complex pattern of abnormal contraction and relaxation in the non-ischaemic inferior regions at baseline; after surgery such abnormalities decreased significantly and tended to revert to normal in many cases. Left ventricular shape in the inferior region was abnormal in 10/13 patients in that there was negative curvature at the interface between the aneurysm and the inferior wall that was corrected to positive after surgery. Regional inferior wall motion and global ejection fraction significantly improved after surgery in these 10 patients. The three patients whose global ejection fraction did not improve showed no inferior negative curvature pre-operatively, nor did they show an increase in inferior wall motion. The results indicate that regional function and shape in inferior, non-ischaemic regions, remote from an anterior aneurysm, are abnormal but potentially correctible if the abnormal mechanical burden imposed on the wall is relieved.

Aged↗
PubMed1994

Elliptic Fourier approximation with application to left ventricular contour analysis.

A computer program for the quantitative analysis of left ventricular wall motion, in standard angiography or echography, was developed based on the center-line model. In order to resolve the uncertainties of the previous implementations, the elliptic Fourier approximation was tested on a large set of left ventricular contour pairs, in various pathological conditions. Fitting a function to the center-line (in the middle of end diastolic and end systolic contours) makes it possible to perform multiple tasks at the same time, in an analytical way and without the need of arbitrary parameters, such as search windows. In doing so, the flexibility and accuracy of this method was demonstrated, more in general, for filtering, interpolation and differentiation of noisy 2D or 3D data. A comparison with standard B-spline was carried out, for both open and closed curves, with sparse or equispaced points. The resulting approximation errors were twice as high as those of the elliptic Fourier decomposition, still preserving smooth direction and curvature. Though already described, this methodology deserves more widespread application.

Algorithms↗