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Biomedical subjects

A Tadei

Publications and source records attributed to A Tadei.

At least 19 recordsLinked to original sources
PubMed1999

Three-dimensional coronary artery MR imaging using prospective real-time respiratory navigator and linear phase shift processing: comparison with conventional coronary angiography.

Respiratory gating with navigator echo is a recent technique to detect diaphragm position in 3D magnetic resonance (MR) coronary angiography. The purpose of our study was to image proximal coronary arteries and to detect significant stenoses in patients with coronary artery diseases and to compare with contrast enhanced angiography results. Twenty patients with coronary artery diseases who were referred for conventional angiography underwent magnetic resonance angiography (MRA). Three-dimensional gradient echo volumes were acquired using cardiac and respiratory gating and fat suppression. Using reformatted oblique planes and maximum intensity projection technique, visualization coronary segments and detection of significant coronary stenoses were made. Eighty-three coronary segments were analyzed. The sensitivity and specificity were 65% and 93%, respectively. The corresponding positive and negative predictive values were 69% and 91%. This study shows the ability to image correctly coronary arteries and to identify proximal stenoses, but image quality need to be improved for an efficiency detection of coronary artery stenoses in clinical practice.

Adult↗
PubMed1999

[Variations of coronary blood flow measured by intracoronary doppler in the acute phase of myocardial infarction before and after revascularization by angioplasty].

The authors studied the changes in coronary blood flow before, during and after reperfusion by angioplasty of the disease coronary vessel responsible for myocardial infarction using intracoronary Doppler. Forty patients aged 60.2 +/- 15.4 years, admitted for primary myocardial infarction (inferior: 22, anterior: 18) were included. Before reperfusion, the peak velocity of the collateral coronary circulation was 14.8 +/- 8.1 cm/s. The flow was bidirectional, mainly retrograde (N = 32), negative (N = 1) or positive (N = 5). The five Rentrop 0 patients had velocities similar to Rentrop 1, 2 or 3 patients (Rentrop 0: 14.9 +/- 6.4 cm/s; Rentrop 1: 12.3 +/- 9.9 cm/s; Rentrop 2: 15.2 +/- 8.2 cm/s; Rentrop 3: 17.5 +/- 6.3 cm/s). Patients with TIMI 3 reperfusion flow had the highest APV Doppler velocities (average peak velocities during the cardiac cycle) (APV TIMI 3 = 20.2 cm/s versus APV TIMI 1 and 2 = 10.9 cm/s, p = 0.05). After angioplasty, the APV was 18.7 +/- 10.4 cm/s (p < 0.001). Diastolic flow was dominant. Seventeen patients had retrograde systolic flow, 12 had minimal systolic flow and 17 had a steep diastolic deceleration slope. Intracoronary Doppler demonstrates the wide range of coronary flow in TIMI 3 flow patients, both from the morphological and the quantitative points of view, which seems to be independent of the presence of residual stenosis and could be related to abnormalities of the microcirculation. This could allow identification of a subgroup of patients at high risk and candidates for a complementary therapeutic intervention (intra-aortic balloon pumping...).

Adult↗
PubMed1999

[MRI quantification of regional variations of left ventricular parietal stress in normal subjects].

The object of this study was to analyse regional variations in end systolic left ventricular wall stress in normal subjects using three-dimensional magnetic resonance imaging (MRI) with excellent spatial resolution. Eight to 12 contiguous short axis sections of the left ventricle were acquired from the apex to the base in apnoea with a rapid echo-gradient sequence in 15 healthy volunteers. The end systolic wall stress was calculated by three methods: Grossman's formula (CR) using the wall thickness and radius of curvature, Janz's formula (CS) using the surfaces, and a three-dimensional approach (C3D) providing a precise calculation of the radius of curvature. The values of wall stress obtained by CS and CR were lower (p < 0.001) at the apex (3.2 and 3.3 10(3) newton/m2 respectively) than at the base (6.9 and 7.1 10(3) newton/m2). There was no difference between the base and apex with the C3D method (8.0 and 9.0 10(3) newton/m2 respectively, NS). The same results were observed at the inferior, lateral, anterior and septal segments with an increase at the base using the CS and CR formulae, the C3D remaining homogeneous in the left ventricle except for the interventricular septum. The lateral wall stress was significantly lower with respect to the interventricular septum in all sections from the apex to the base, irrespective of the method of calculation used. The differences in regional wall stress from the base to the apex reported in healthy subjects seem to be related to an underestimation of left ventricular wall thickness and an underestimation of the radius of curvature rather than to a physiological phenomenon.

Adult↗
PubMed1998

[Measurement of the left ventricular mass using MRI with automatic determination of the endocardial and epicardial contours].

This study describes a method of automatic border detection of the left ventricular endocardium and epicardium associating three methods of segmentation (increase of region, border detection and adaptive threshold), applicable to the evaluation of ventricular mass and volume by magnetic resonance imaging. Despite slight underestimation, the spin-echo sequence used in 9 small pigs provided a value of left ventricular mass close to that observed ex vivo (r = 0.97, SEE = 6.05 g). Clinical validation using a rapid gradient-echo sequence was undertaken and compared with manual border detection carried out by three independent, trained operators. The study population included healthy subjects and patients with global or segmental left ventricular dysfunction with or without ventricular deformation. The correlations between automatic and manual detection were satisfactory both for calculation of left ventricular mass (r = 0.93, SEE = 13 g) and measurement of surfaces (r = 0.91, SEE = 1.4 cm2). The concordance of the two methods was confirmed by the Bland and Altman test. Cardiac magnetic resonance imaging may provide accurate and reproducible measurements of left ventricular mass within acceptable acquisition and image processing times for routine use. Although the clinical value of such a method is accepted both for establishing the prognosis and guiding management, studies of the cost/efficacy ratio should be undertaken to situate magnetic resonance imaging with respect to other non-invasive techniques of investigation of left ventricular function.

Adult↗
PubMed1997

[Value of MRI with injection of gadolinium in the diagnosis of mitral ring abscess. Apropos of a case].

Transoesophageal echocardiography is the investigation of choice for the diagnosis of valvular vegetations in infectious endocarditis but the diagnosis of an associated ring abscess is sometimes difficult especially in patients with valvular prostheses or calcifications which are in important source of artefacts. The authors report a case of mitral annular abscess confirmed at surgery and comment on the diagnostic and prognostic value of cardiac MRI. MRI showed an abnormal cavity directly related to the mitral annulus and separated from the left ventricle by a low intensity signal which increased after injection of gadolinium suggesting an inflammatory origin and therefore arising from the abscess. The cavity was heterogeneous in T1 associating zones of low intensity with high intensity signals increasing in T2 on the second echo (thrombus and necrosis). Cine-MRI showed non communication between the abscess cavity and the left ventricle or atrium.

Abscess↗
PubMed1997

[Results of radiofrequency ablation of the atrioventricular junction in patients with refractory atrial arrhythmia and severe impairment of the left ventricular systolic function].

Results of radiofrequency ablation of the atrioventricular junction on functional capacity and left ventricular systolic function were assessed in 8 patients (aged 68 +/- 12 years) with refractory atrial fibrillation and severe left ventricular dysfunction, the mean ejection fraction being 31 +/- 11% (range: 20-48%). A clinical, echocardiographic and angioscintigraphic follow-up was performed 24 hours (basal), 3 and 6 months after the procedure. During follow-up, all patients reported the disappearance of palpitations and tiredness, a significant and early regression of effort dyspnoea from average NYHA Class 3.4 +/- 0.7 to 2.2 +/- 0.4 (M3), (p < 0.01), a decrease in end diastolic echocardiographic dimensions (from 57 +/- 10 to 52 +/- 9 mm (M3); p < 0.05) resulting in an increase in fractional shortening from 26 +/- 7% to 34 +/- 6%; p < 0.05. The isotopic EF increased from 31 +/- 11% to 42 +/- 12% (M3) (p < 0.01), and attained 48 +/- 12% (M6). This study shows that controlling the frequency and regularity of cardiac rhythm by ablation of the atrioventricular junction in patients with refractory AF and left ventricular dysfunction results in functional and haemodynamic improvement, especially when there is no apparent underlying cardiac disease. This suggests that this method should be proposed in all patients with refractory atrial fibrillation and left ventricular dysfunction.

Aged↗
PubMed1996

[Increase of sialic acid concentration in the plasma of patients with coronary disease].

OBJECTIVES: Plasma levels of sialic acid are elevated in patients with coronary heart disease. We evaluated the specificity of this increase and attempted to correlate it with the severity of coronary lesions. METHODS: Total plasma sialic acid levels measured in 60 control subjects were compared with that in 135 patients with heart disease requiring coronarography. RESULTS: Plasma levels of sialic acid were significantly higher in patients (664 +/- 146 mg/l) than in controls (584 +/- 100 mg/l). In the group of patients, sialic acid level was only increased in those with coronary lesions - infarcts (738 +/- 166 mg/l) and angina (664 +/- 121 mg/l) - but was not raised above normal levels in those with other heart diseases (cardiomyopathy, valve failure, etc.). There was a positive correlation (p < 0.001) between raised sialic acid level and the severity of the coronary lesions as measured on coronarography. CONCLUSIONS: The elevated level of sialic acid in patients with coronary heart disease could be related to disorders in cell adhesion.

Adult↗
PubMed1995

Radionuclide angiography and magnetic resonance imaging: complementary non-invasive methods in the diagnosis of constrictive pericarditis.

Constrictive pericarditis presents with a suggestive clinical picture, and its diagnosis is based on a haemodynamic pattern revealing impaired ventricular filling. In this study of 15 patients with pure isolated constrictive pericarditis, we attempted to evaluate the diagnostic value of two non-invasive methods not usually employed in this indication: radionuclide angiography (RNA) and magnetic resonance imaging (MRI). Whilst RNA permits analysis of the functional pattern of the global and segmental left ventricular filling impairment, MRI allows measurement of the thickness of the pericardium. RNA revealed increased early diastolic filling as evidenced by a shorter one-third filling time (TF1/3; P<0.0001 with respect to a normal population), a higher peak filling rate (PFR; P<0.01) and its early occurrence (P<0.001), increased one-third and mid diastolic filling fractions (P<0.01), and the ratio of the PFR over the peak ejection rate (P<0.01). During late diastole, the atrial filling fraction decreased (NS). The patients with constrictive pericarditis also showed a decrease in the physiological filling asynchrony, as assessed by segmental evaluations. Seven patients underwent MRI. The pericardium was thickened in all the patients, varying from 6 to 14 mm (normal: 2.5+/-0.7 mm), without any systolo-diastolic variation. Pericardial thickening appeared as a dark low-intensity signal band, demonstrating the fibrocalcific nature of the pericardial contents. Sagittal and coronal cross-sections were particularly well-suited to show the non-uniformity of the pericardial thickening. These results indicate that RNA and MRI are complementary non-invasive methods, and can provide the functional and anatomical information required for the diagnosis of constrictive pericarditis.

Adult↗
PubMed1994

[Recanalization of chronic occlusions and myocardial infarction occurring during reocclusion. Apropos of 2 cases].

Although recent techniques have significantly improved the frequency of disobliteration of chronic occlusions, the potential complications in terms of mortality, emergency bypass surgery and myocardial infarction seem as common as in angioplasty of stenosis. Of these complications, the occurrence of infarction during reocclusion at the site of angioplasty has not been described and even been refuted by some authors. We report two cases of acute infarction, one of which was transmural, occurring during late reocclusion after disobliteration of a chronically occluded artery.

Aged↗
PubMed1994

[Arrhythmia and conduction defects in polymyositis].

The prevalence of cardiac complications of dermatomyositis and polymyositis is generally underestimated. The authors report the case of heart block as the presenting symptom of the disease, situated in the atrioventricular node. Initially paroxysmal, it eventually became permanent. It was associated with atrial (fibrillation and flutter) and ventricular hyperexcitability (ventricular tachycardia in runs). Myocardial biopsy provided histological proof of the cardiac disease and the definitive link between the nodal conduction defect and the polymyositis.

Adult↗
PubMed1994

[Value of magnetic resonance imaging in cardiac sarcoidosis. Apropos of a case].

The authors report the value of magnetic resonance imaging (MRI) in a case of cardiac sarcoidosis presenting with syncopal ventricular tachycardia (VT). The images were acquired in a monomorphic multiplane echo spin sequence. A 25 millisecond interval was chosen for the weighted T1 sequence. A second weighted T2 sequence using an interval of 70 milliseconds was then performed. The acquisitions were recorded in these planes axial, sagittal and coronal. The thickness of the sections was 8 mm. MRI was useful in locating the exact site and extent of the lesions; this enabled the operators to perform "guided" endomyocardial biopsies. In the weighted T1 sequences, these biopsies showed zones of increased intramyocardial signal density, more pronounced on the second weighted T2 sequences. Moreover, it was possible to follow up the outcome of these lesions with steroid therapy and observe their partial regression. These non-specific appearances may be observed in all inflammatory conditions but, in the context of systemic sarcoidosis, are very suggestive of cardiac involvement. In view of the clinical latency of cardiac sarcoidosis and its poor prognosis, the non-invasive character of MRI should make this a routine investigation in all patients with systemic sarcoidosis.

Adult↗
PubMed1993

[Thallium 201 myocardial scintigraphy and left branch block. Comparative value of exercise test and dipyridamole test].

Stress Thallium 201 myocardial scintigraphy in patients with left bundle branch block often shows reversible septal perfusion defects even in the absence of coronary artery disease. This phenomenon seems more common when the patients have tachycardia. With the working hypothesis that dipyridamole stress testing, which does not greatly increase the heart rate, would be more appropriate than exercise stress testing to unmask coronary artery disease in this condition, the authors compared the results of two Thallium 201 scintigraphies performed after exercise and then after dipyridamole under the same conditions three weeks later, in 67 patients with complete left bundle branch block. Scintigraphy showed one or more reversible perfusion defects in 64/67 patients after exercise but only 32/67 patients after dipyridamole (p < 0.001). There was poor uptake in the septal region in 59 patients (88%) after exercise and in 25 patients (37%) after dipyridamole (p < 0.001). The specificity was evaluated in 23 patients estimated to have no coronary artery disease. If only unequi vocal perfusion defects were considered, the specificity after dipyridamole was higher than that after exercise, increasing from: 35% to 83% for septal defects (p < 0.01); 65% to 96% for anterior wall defects (p < 0.05); 61% to 87% for inferior wall defects (p < 0.05); 57% to 91% for apical defects (p < 0.01); 17% to 83% overall (p < 0.001). Lower values but with a comparable difference were observed when all forms of hypofixation (even minimal) were taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Value of radionuclide ventriculography and magnetic resonance imaging in the diagnosis of constrictive pericarditis].

In suggestive clinical presentations, the diagnosis of constrictive pericarditis is confirmed by the haemodynamic findings of impaired ventricular filling (diastole). In this study of 15 patients with pure constrictive pericarditis, the diagnosis value of two non-invasive techniques little used in this indication until now was examined: radionuclide ventriculography (RV) and magnetic resonance imaging (MRI). The RV provides a "functional" diagnosis through the analysis of global and segmental left ventricular filling whilst MRI provides anatomical details of the pericardial thickening. Diastolic dysfunction on RV presented as an increased early diastolic filling time as shown by a shortening of the interval to third filling T1/3R (p < 0.0001), an increased peak diastolic E wave velocity (p < 0.01) and early onset (p < 0.001), increased one third (FR 1/3) and mid (FR 1/2) diastolic filling fractions (p < 0.01) and of the E wave velocity to maximal systolic ejection velocity (S) ration (p < 0.01). The atrial contribution to filling in end diastole decreased (NS). Asynchronous filling, shown by dispersion of the times of onset of segmental early diastolic E peak velocities (delta tE) or of one third diastolic filling delta T1/3R, decreased. Seven patients underwent MRI. Pericardial thickening was present in all patients. The pericardium varied from 6 to 14 mm thick (normal 2.5 +/- 0.7 mm), without any systolo-diastolic variation. The thickening was seen as a dark low intensity signal, indicating the fibro-calcific character of the tissues. Sagittal and coronal views clearly demonstrated the non-uniformity of pericardial thickening.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Circulatory changes of the middle cerebral artery during syncopes produced by the head-up tilt test].

Velocity of the middle cerebral artery was recorded with transcranial pulsed doppler in 10 neurally-mediated syncopes elicited by 60 degrees head-up tilt test. Mean arterial blood pressure decreased by -36 +/- 16 percent (P < 0.0001) and heart rate by -6 +/- 27 percent (P < 0.05). Mean middle cerebral artery velocity decreased by -48 +/- 16 percent (P < 0.0001); Pourcelot's resistance index increased by 74 +/- 47 percent (P < 0.0001) and Gosling's pulsatility index by 218 +/- 111 percent (P < 0.0001). However, resistance normalized with mean arterial pressure showed no significant increase (+ 14 +/- 28 percent; NS). The decrease in diastolic velocity as well as mean arterial blood pressure and heart rate was significantly lower when loss of consciousness occurred. Contrary to those of other authors, our results do not support the hypothesis that syncopes result from a paradoxical cerebral vasoconstriction since no significant changes were observed in resistance normalized with mean arterial pressure. Thus, decrease in cerebral perfusion is likely to be the result of a decrease in cerebral perfusion pressure.

Adult↗
PubMed1992

[Natural history of syncope of undetermined origin with inconclusive electrophysiologic examination].

Between 1985 and 1986, 109 consecutive patients with unexplained syncope after clinical and standard electrocardiographic examination underwent electrophysiological investigation. In 61 cases (56%), 35 men and 26 women (mean age 69 +/- 13 years) no firm diagnosis could be made. These patients were the study group. Underlying cardiac disease was present in 23%, coronary artery disease in 10% of cases. In 33 cases, the basal ECG was normal (54%). Sixty patients (one lost to follow-up) were studied over an average of 38 +/- 12 months. Global mortality and recurrence rate were 13 and 18% respectively. There were no sudden deaths in the 8 fatalities. The mechanism of the 17 recurrent syncopes was cardiac in 5 cases, vasovagal in 1 case, uncertain in 11 cases. Of the 5 cardiac syncopes, 3 were related to 3rd degree atrioventricular block occurring 7 to 49 months after the initial electrophysiological investigation. No predictive criteria of recurrence could be identified. Empiric treatment proposed to 28% of patients did not prevent recurrent syncope and did not improve global survival. Inconclusive electrophysiological investigation of patients with unexplained syncope defines a population with a low risk of sudden death. Recurrent syncope is common. The recurrence of symptoms is an indication to repeat the aetiological investigations which should include a tilt-test ot another electrophysiological investigation. Empiric treatment has not been shown to be effective.

Actuarial Analysis↗
PubMed1991

[Isolated impairement of the regional filling of the left ventricle in the coronary patient with normal systolic function. A study by isotopic ventriculography during rest].

The aim of this study was to assess whether resting radionuclide angiography could detect isolated regional left ventricular filling abnormalities due to chronic ischemia. The authors studied global and regional (10 segments) variations of LV volume using an original computerised system in 29 patients with single vessel coronary artery disease and normal systolic function without any other known pathology which could have altered left ventricular filling. Purely diastolic regional wall abnormalities were detected in presumed ischemic territories in over 60% of patients. They were then observed mostly in early rather than late diastole and affected the chronological indices (time to 1/3 LV filling, or to peak early diastolic filling rate) more than those of velocity (peak E or A velocities) or volume (filling fraction at 1/3 and half-diastole or that due to atrial contraction). They suggested delayed relaxation in these regions. These segmental changes are associated with a significant increase in asynchronous filling as judged by the variation in the intervals to peak early diastolic filling (tE) (p less than 0.001) and to one third filling (T 1/3R) (p less than 0.02), in the absence of increased physiological asynchronous contraction. An inversed relationship was observed (p less than 0.01) between the global value of peak early diastolic velocity and the indices of early diastolic asynchronous filling tE (r = -0.48) and T1/3R (r = -0.54). As previously reported, these regional abnormalities are, however, generally too small to cause changes in global diastolic function.

Adult↗