Search PubMed⌕ Search

Biomedical subjects

M Villani

Publications and source records attributed to M Villani.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Ventricular nodal reentry tachycardia without ventricular dilatation: diagnosis and treatment by radiofrequency catheter ablation].

Bundle branch reentry tachycardia has been reported in patients with left ventricular dilatation, especially in those with dilated cardiomyopathy and aortic regurgitation. These patients show aspecific intraventricular conduction delay on the ECG and a prolonged H-V interval at the electrophysiologic study. We report 2 cases of bundle branch reentry tachycardia in patients without left ventricular enlargement to help the correct diagnosis of the arrhythmia. A correct diagnosis is very important because bundle branch reentry tachycardia is easily and safely treated by right bundle transcatheter radiofrequency ablation. We also report electrophysiologic characteristics we found during the study and the ablation: -contrary to the data reported in literature, at ventricular tachycardia starting, modifications of the V-V interval are not always preceded by similar variations in the H-H interval. -during right bundle radiofrequency ablation, a QRS narrowing may precede right bundle branch block appearance. This QRS normalisation should induce to continue and not to stop energy delivering.

Aged↗
PubMed1995

LGANN: a parallel system combining a local genetic algorithm and neural networks for the prediction of secondary structure of proteins.

In this work we describe a parallel system consisting of feed-forward neural networks supervised by a local genetic algorithm. The system is implemented in a transputer architecture and is used to predict the secondary structures of globular proteins. This method allows a wide search in the parameter space of the neural networks and the determination of their optimal topology for the predictive task. Different neural network topologies are selected by the genetic algorithm on the basis of minimal values of mean square errors on the testing set. When the alpha-helix, beta-strand and random coil motifs of secondary structures are discriminated, the maximal efficiency obtained is 0.62, with correlation coefficients of 0.35, 0.31 and 0.37 respectively. This level of accuracy is similar to that previously attained by means of neural networks without hidden layers and using single protein sequences as input. The results validate the neural network topologies used for the prediction of protein secondary structures and highlight the relevance of the input information in determining the limit of their performance.

Algorithms↗
PubMed1995

[Human dirofilariasis in southern Italy. III. The Molise region].

A case of subcutaneous human dirofilariasis associated with Dirofilaria repens in the arm of a 9-year-old child resident in Campobasso is described. It is the first report of the nematode in the Molise region. Blood samples taken from dogs in the same region, confirmed the presence of D. repens microfilariae in the natural reservoir, few km from the clinical case.

Animals↗
PubMed1994

[Immigrant child: cognitive research on the state of health in Rome].

Surveying and assessing chemical statistic data on the state of health of immigrant children in Rome, the authors wish a greater engagement of political administrative authorities. In this way children, whose families find integration in our society hard, could at least have an effective medical assistance.

Adolescent↗
PubMed1993

Automatic analysis of high resolution atrial activation in mitral valve stenosis.

High resolution P-waves of 28 patients having a mean age of 45 years and affected by isolated mitral valve stenosis (nine of whom showed paroxysmal atrial fibrillation) have been compared with those obtained from 30 healthy subjects about 35 years old. Our primary aim was to characterize the signal-averaged P-wave in mitral valve stenosis. Parameters which differed between the two groups in time domain analysis were the P-wave duration, the abscissa of the maximum positive voltage amplitude, the peak-to-peak amplitude and the integrated voltage-time product, which turned out to be greater in the patient class than in the healthy set; furthermore, in the frequency domain analysis, amplitudes in the range from 37 to 60 Hz were greater in healthy subjects than in patients. A successive analysis carried out to predict those patients with mitral valve stenosis who are at risk of developing paroxysmal atrial fibrillation showed that the P-wave duration and the amplitudes (in the range 60-106 Hz) were the most distinctive parameters, but, unfortunately, without any significant difference with respect to those of patients with mitral valve stenosis alone. Finally, some correlations between the age, the P-wave duration and the left atrial diameter of patients, were revealed to exist only in patients affected by episodes of atrial fibrillation.

Adult↗
PubMed1993

[Cor triatriatum associated with inter-atrial defect: diagnosis by transesophageal echocardiography].

Cor triatriatum (CT) is a rare malformation consisting of a fibromuscolar membrane that subdivides the left atrium in a postero-superior (or accessory) chamber and an antero-inferior chamber (true left atrium, containing the left atrial appendage). In its classic form, the accessory chamber receives the pulmonary veins and communication with the left atrium is accomplished by way of one or more fenestrations in the membrane. The malformation is usually isolated, but in about one in four patients is associated with other congenital defects of a complex nature. We describe a case of CT associated with atrial septal defect, in which transthoracic echocardiography failed to document the existence of CT membrane, while this abnormality was clearly seen and defined by use of transesophageal echocardiography. The patient was a 26 year-old girl, presented at our outpatient clinic after an episode of palpitations and dyspnea, which lasted for two hours. She suffered of mild dyspnea on exertion during the last three months. Physical examination revealed the typical findings of an atrial septal defect (ASD), and the electrocardiogram revealed right bundle branch block. The two-dimensional echocardiography disclosed an ostium secundum ASD with left to right shunt; dilatation of the right cavities; paradoxical movement of the interventricular septum. A small linear echo originating from the lateral wall of the left atrium, with no evidence of turbulent flow on pulsed wave Doppler and color flow examination, was interpreted as an artifact. Transesophageal echocardiography clearly visualized a tense, bulging membrane separating left atrium into two chambers.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Multiple↗
PubMed1992

[Ventricular late potentials in hypertrophic cardiomyopathy: personal contribution and analysis of the literature].

BACKGROUND: Patients with hypertrophic cardiomyopathy are at increased risk of sudden death. Recently it has been investigated whether late potentials can be useful markers of that risk in such patients, with discordant results. The aim of our study was to detect a correlation, if any, between late potentials, ventricular tachycardia and the hypertrophy extension. METHODS: Twenty-five patients were enrolled, 19 males and 6 females, mean age 40.40 +/- 15.02 years. Each underwent 24h Holter monitoring, averaged ECG, M-Mode and 2-D Echo. The hypertrophy was considered extensive (septum and free wall) or non extensive (septum and/or apex). RESULTS: Late potentials of a mean duration of 37 +/- 14.83 ms were recorded in 5/7 patients with documented ventricular tachycardia vs in none of the non tachycardia group. Sensibility was 100%, specificity 71% and predictive value 100%. Late potentials were present in 8.3% of patients with non extensive and in 30.8% of patients with extensive hypertrophy (p = NS). CONCLUSIONS: From our data it seems that extensive hypertrophy is present in about half of patients with hypertrophic cardiomyopathy, and this roughly correlates with a more frequent ventricular tachycardia and with late potentials. Furthermore, late potentials are strictly related to the incidence of ventricular tachycardia in this disease, just as in ischemic heart disease or in idiopathic dilated cardiomyopathy. The small number of our cases may not be sufficient to reach a significant statistical correlation between late potentials and hypertrophy, but we believe that the trend is very promising.

Action Potentials↗
PubMed1992

[Paroxysmal atrial fibrillation in patients with chronic ischemic cardiopathy: a study of high-resolution atrial activation].

BACKGROUND: Patients with ischemic heart disease and episodes of paroxysmal atrial fibrillation are at major risk of stroke. In order to prevent such episodes, through the identification of patients prone to atrial fibrillation, we investigated the high-resolution atriogram of 65 patients with chronic ischemic heart disease, 54 male and 11 female, mean age 60.22 +/- 9.04 years. Based on previous documented episodes of atrial fibrillation, the patients were divided into two groups: group A, 45 males and 3 females, mean age 58.92 +/- 7.68 years, without atrial fibrillation; group B, 9 males and 8 females, mean age 63.88 +/- 11.6 years, with atrial fibrillation. RESULTS: High resolution atrial duration (100-300 Hz) in group B (with atrial fibrillation) was higher than in group A (without atrial fibrillation) (140.59 +/- 16.85 ms vs 121.77 +/- 11.27 ms, p < 0.001); Non filtered atrial duration (0-300 Hz) was not different between the two groups, A and B (118.54 +/- 10.96 ms vs 123.53 +/- 18.77 ms, p = NS); The prevalence of late atrial potentials was higher in group B than in group A (60.8% vs 7.1%, p < 0.001); No relation was observed between high resolution atriogram data and echocardiographic measurements; Sensibility was 82%, specificity 81%, and predictivity 60%. CONCLUSIONS: Data from our study show that high resolution electrocardiography is a valid tool for identifying patients prone to atrial fibrillation. Such patients can be identified by the presence of "late atrial potentials" that, like late ventricular potentials for ventricular tachycardia, are correlated with atrial fibrillation. Nevertheless, a larger cohort of patients is necessary to confirm these results.

Aged↗
PubMed1990

Reoperations on heart valve prostheses: an analysis of operative risks and late results.

To evaluate risks and complications of reoperations on heart valve prostheses, we reviewed data on 183 patients who underwent reoperation because of prosthetic valve malfunction. The incremental effect of the redo procedure on hospital mortality and morbidity was studied by comparing primary and reoperative procedures and analyzing a series of possible predisposing factors. Late survival after first and second reoperations was computed, and possible determinants of late mortality were examined. Overall operative mortality was 8.7%; emergency operation (p = 0.0001), previous thromboembolism (p = 0.05), and advanced New York Heart Association functional class (p = 0.031) were the independent determinants. In a series of 1,355 patients having primary or secondary isolated valve replacement, the redo procedure was a significant risk factor in the univariate analysis (p = 0.025) but not in the multivariate analysis except for the subset of patients having mitral valve replacement (p = 0.052). The postoperative course was quite complicated, as evidenced by the long mean stay in the intensive care unit (mean stay, 3.8 days; longer than 2 days for 26% of the survivors). Nevertheless, postoperative complications were not significantly greater after a redo procedure than after a primary operation. Actuarial survival at 7 years was 57.3% +/- 8%. A comparison with a nonhomogeneous series from our institution did not demonstrate significant differences. In the subset of 16 patients having a second reoperation, late survival was 37.8% +/- 16% at 2 years. Advanced New York Heart Association class (p = 0.0001), double prosthetic valve dysfunction (p = 0.003), and any indication other than primary tissue failure (p = 0.06) were determinants of late mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioprosthesis↗
PubMed1990

[The midterm clinical results of myocardial revascularization with the internal mammary artery].

After a 3-year (1985-1988) experience of myocardial revascularization using internal mammary artery (AMI) grafts and after having excluded (1986) an higher operative mortality and morbidity, clinical medium-term results have been analysed. The first 144 patients discharged alive after AMI bypass surgery in 1985 were clinically evaluated, with a mean interval of 21 months from surgery (range: 5-29 months). Exercise electrocardiographic test was performed by 100 patients, and angiography repeated in 15. Actuarial survival function was estimated by Cutler-Ederer method: 2-year actuarial survival was 99.3 +/- 0.7% (94 +/- 1.8%, when operative deaths were included). Non fatal myocardial infarction occurred in 3 patients and, at follow-up, 26 were symptomatic for angina: 2 patients underwent re-operation and 2 angioplasty. Two years after AMI bypass surgery, actuarial estimate of ischemic event-free patients was 70.9 +/- 4.5% (67.7 +/- 4.5%, when operative deaths were included): 73 out of 100 exercise tests were negative for both angina and ischemia, although only 43 patients, reached maximal work load; 9 were positive for both angina and ischemia and 18 for ischemia only. All patients who underwent angiographic evaluation (15 patients, 11 of whom because of angina relapse) had AMI grafts open, while in only 4 patients all the implanted grafts were open.

Aged↗
PubMed1990

Late potentials in idiopathic dilated cardiomyopathy.

Twenty-five patients with idiopathic dilated cardiomiopathy were investigated in order to evaluate the role of late ventricular potentials as possible markers of ventricular tachycardia or sudden cardiac death. Holter monitoring showed ventricular tachycardia in 9 patients (group A) all of whom had late ventricular potentials, (mean +/- SD length 37.22 +/- 15.83 ms and mean +/- SD voltage 5.62 +/- 2.78 microV). Mean +/- SD ejection fraction in this group was 20 +/- 9.39%. In 16 patients (group B), without ventricular tachycardia, means +/- SD ejection fraction 27.5 +/- 8.17%; late ventricular potentials were recorded in 2 patients. During the follow-up period (means +/- SD 11.53 +/- 7.19 months), 3 patients underwent heart transplantation, 2 patients underwent pace-maker implantation and 2 patients from the ventricular tachycardia group died one from sudden cardiac death and the other from progressive heart failure. No significant differences were found in the ejection fraction either between the ventricular tachycardia and the non-ventricular tachycardia group, or between the late ventricular potentials and the non-late ventricular potential groups. Negative data were also obtained when we tried to find a correlation between the ejection fraction and late ventricular potential length and/or voltage. Good results were observed with regard to sensitivity (100%), specificity (87%) and predictive accuracy (81%) but follow-up data did not specify a definite prognostic value for late ventricular potentials. The Authors conclude that late ventricular potentials are markers of patients with idiopathic dilated cardiomyopathy who are prone to ventricular tachycardia. However, the role of late ventricular potentials in sudden cardiac death is still uncertain.

Adolescent↗
PubMed1989

Heart transplant rejection detected by signal averaged QRS analysis. Preliminary results.

Detailed QRS wave analysis from the limb leads of the surface high resolution electrocardiograms recorded in five cyclosporine-treated heart transplant recipients gave good correlation with the corresponding results of endomyocardial biopsy. That is when the result of the biopsies has identified the presence of rejection, a concomitant (p = 0.001) variation in some parameters of the QRS has been observed. The reproducibility of such parameters (established by means of the correlation coefficient r) gave r values ranging from 0.6 up to 0.93. The correlation regarded parameters analyzed both in time and frequency domain. Biopsy results were divided into two classes on the basis of the presence or absence of rejection. The most significant parameters obtained from high-frequency (25-300 Hz) ECGs within a few hours of each biopsy were: a) the total high-frequency voltage amplitude Vt of the QRS and the voltage amplitude of its initial Vi and middle thirds Vm; b) the peak voltage amplitude Vp of the QRS; c) the QRS duration L; d) the integrated voltage time product I of the QRS; e) three mean voltage amplitudes V5, V6, V7, of the power spectral density constructed on the basis of the 512-point fast Fourier transform applied on each recording. The above mentioned parameters appear to be useful in predicting the biopsy result in terms of the presence or absence of rejection.

Adolescent↗
PubMed1989

[Incidence and significance of ventricular arrhythmia after surgical correction of Fallot's tetralogy].

Patients may die suddenly after surgical repair of tetralogy of Fallot. Ventricular arrhythmias (VA) have been considered the possible cause of sudden death in such patients by many Authors. We evaluated the incidence and severity of VA in a group of 65 patients (25 females and 40 males) after surgical repair of tetralogy of Fallot. The age at the time of follow-up varied between 8 and 47 years. We divided our population into 4 groups (A, B, C, D) according to the surgical results (poor and good) and to the age of total correction (less than 12, greater than 12 years). We tested the presence and severity of VA in the different groups of patients and we found a significant difference in the incidence of VA between patients who underwent surgery before and after the age of 12 years (p = 0.0083). The surgical result did not show a significant relation with VA (p = 0.47). Among the patients submitted to surgical repair in the adult age, however, more serious VA are present in those with poor surgical result, and both our cases of sudden death occurred in this kind of patient. We speculate that postoperative ventricular arrhythmias are related to right ventricular function, which in turn appears to be worse in patients who underwent surgical correction at a later age. At last only perspective trials will be able to assess the significance of VA and their relationship with sudden death in this kind of patient.

Adolescent↗