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Biomedical subjects

A Nava

Publications and source records attributed to A Nava.

At least 73 records · Page 4Linked to original sources
PubMed1995

Arrhythmogenic right ventricular cardiomyopathy in young versus adult patients: similarities and differences.

OBJECTIVES: This study was designed to evaluate and compare the patterns of arrhythmogenic right ventricular cardiomyopathy in young people and adults. BACKGROUND: Few data are available on this cardiomyopathy in young people because clinical and morphologic findings considered pathognomonic are normally based on observations in adults. However, a familial occurrence with a probable genetic transmission led to the study of children and to early detection of this disease, in which sudden death has been reported even in young people. METHODS: Seventeen young patients with arrhythmogenic right ventricular cardiomyopathy diagnosed at a mean age +/- SD of 14.9 +/- 4.9 years were studied. Clinical, electrocardiographic, echocardiographic, cineangiographic and biopsy findings were compared with those of 19 adult patients whose condition was diagnosed at a mean age of 38.1 +/- 13.4 years. RESULTS: Syncope occurred in 23.5% of the young patients but in none of the adults (odds ratio of familial sudden death 5.54, p = 0.1). Ventricular couplets (odds ratio 16.0, p = 0.004) and subtricuspid bulging on echocardiography (odds ratio 5.95, p = 0.036) were prevalent in the young group. Cineangiographic data in the two groups were similar, except that more hypokinetic areas were found in adults (odds ratio 4.44, p = 0.05). Morphometric analysis of biopsy sections showed a greater amount of fibrous tissue in the young patients (p = 0.04) and a prevalence of fatty tissue in the adults (odds ratio 12, p = 0.005). During an equivalent follow-up time (mean 7 years), two young patients died suddenly, and two had ventricular fibrillation in the absence of antiarrhythmic therapy. CONCLUSIONS: The pathognomonic criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy in adults are also valid for young people. Sudden or aborted death occurred frequently in young untreated patients.

Adolescent↗
PubMed1995

Ocular vaso-occlusive disease in primary antiphospholipid syndrome.

PURPOSE: To evaluate the ocular involvement in patients with the primary antiphospholipid syndrome. METHODS: The authors performed a cross-sectional ophthalmologic study of 17 patients with the primary antiphospholipid syndrome. Retinal fluorangiography was performed in 13 patients. RESULTS: Visual symptoms were described by ten patients. Visual acuity was markedly decreased in five eyes. Conjunctival telangiectases and microaneurysms, in addition to single instances of bilateral episcleritis and limbal keratitis, were the anterior segment findings. Fundus abnormalities were present in 15 patients. Venous tortuosity was the most common finding but there were instances of optic disc edema, vitreous hemorrhages, cotton-wool spots, vitreous bands, serous detachment of the macula, and retinal capillary abnormalities. Fluorangiography showed vaso-occlusive retinopathy in six eyes (5 patients, 29%). Choriocapillary vessel occlusion was observed in two eyes (1 patient) and binocular reticular degeneration of pigmentary epithelium was present in another case. CONCLUSION: The eye is frequently involved in the primary antiphospholipid syndrome, and serious ocular damage may occur. Detailed ophthalmologic evaluation is warranted in these patients.

Adult↗
PubMed1995

A new locus for arrhythmogenic right ventricular cardiomyopathy (ARVD2) maps to chromosome 1q42-q43.

Autosomal dominant arrhythmogenic right ventricular cardiomyopathy (ARVD, MIM 107970) is one of the major causes of juvenile sudden death. We have previously assigned the disease locus to chromosome 14q23-q24. Here we report on a novel variant of ARVD, which is transmitted associated to 1q42-q43 and is characterized by a concealed form, showing effort-induced polymorphic tachycardias. Since both loci ARVD1 and ARVD2 map in proximity of alpha-actinin genes, the possible implication of these myofibrillar proteins in the pathogenesis of ARVD is discussed. Two additional ARVD families, tested with markers of chromosomes 1q42-q43 and 14q23-q24, failed to show linkage, providing evidence of further genetic heterogeneity.

Actinin↗
PubMed1995

[High-resolution electrocardiography in 102 young healthy subjects].

BACKGROUND: The aim of this study was to evaluate the normal values of the most common indexes used in the analysis of ventricular late potential in 102 young male subjects. METHODS: The recordings were performed by means of a Marquette electronics Hi-Resolution ECG Mac 15, with filters at 25-250 Hz, 40-250 Hz and 80-250 Hz. The parameters obtained were: filtered QRS duration (QRSD), high-frequency low-amplitude signals duration (HFLA), and the root mean square of the signal expressed in the terminal portion of QRS (RMS). The body surface was also evaluated. RESULTS: QRSD (121.23 ms-113.9 ms-99.9 ms); RMS (105 uV-42.77 uV-34.3 uV); HFLA (17.5 ms-29.3 ms-29.3 ms). The comparison between our results and those proposed by other authors for normal subjects showed different results, particularly concerning the filtered QRS duration. We suppose that these discrepancies may be due to the different instrumentations used and to the different age and sex of the study population. CONCLUSIONS: From these results we confirm that a normal range for each index must be done for homogeneous groups of subjects for age and sex, in healthy subjects as well as for different heart disease.

Adolescent↗
PubMed1995

[The prevalence of the Wolff-Parkinson-White syndrome in a population of 116,542 young males].

Since 1988 to 1992 we analyzed 116,452 consecutive 12-lead electrocardiograms belonging to the entire cohort of 18-year old young boys resident in Padova, Treviso, Rovigo, Venezia, Belluno area (2,834,000 inhabitants). We identified 173 cases of overt WPW pattern (short PR interval, delta wave, anomalous configuration of QRS complex) with a calculated incidence of 1.48/1000. Accessory pathway location was: left free wall (70 patients), right free wall (39 patients), postero-septal (37 patients), antero-septal (15 patients) and undetermined (12 patients). Sixty patients (34.6%) complained of different symptoms as palpitations, near syncope and dizziness. Fifty-three patients (30.6%) went in a regular sport activity. Twenty-four hour Holter monitoring (41 patients) and exercise stress test (43 patients) did not show sustained tachyarrhythmias; intermittent preexcitation was recorded in 23 and 32 patients, respectively. Two-dimensional echocardiogram (68 out of 173) was normal in 44 patients, while 24 showed minor cardiac abnormalities with two major disease; mitral valve prolapse was diagnosed in 8 patients. On the basis of transesophageal (24 patients) or intracardiac (5 patients) electrophysiologic study, 11 patients were considered at high risk for sudden death. Eight of them suffered from spontaneous symptoms.

Adolescent↗
PubMed1994

QT-interval variability in hypertrophic cardiomyopathy patients with cardiac arrest.

We studied long-term variability of QT-dispersion in three patients with hypertrophic cardiomyopathy (Maron III) and ventricular fibrillation. Late potentials were absent on signal-averaged electrocardiogram. ST-segment depression was recorded in all three patients at Holter monitoring, and in two during exercise stress testing, nonsustained ventricular tachycardia was present in only one patient. The maximal correct QT-interval and corrected QT-dispersion (QTcd) were measured retrospectively, both off-drug and under treatment with amiodarone and beta-blocker (two patients), or sotalol alone (one patient). Ten age- and sex-matched normal subjects, and 13 hypertrophic cardiomyopathy patients without ventricular arrhythmias formed the control groups. QTcd-values in the control groups never exceeded 80 ms and mean values of 30.1 +/- 10.1 ms and 44.1 +/- 7.9 ms respectively, were found. During long-term follow-up, QTcd increased progressively in two of the three patients with ventricular fibrillation, and at the time of the event all showed a value > 100 ms. Sotalol, but not the amiodarone reduced QTcd. QTcd seems to be a powerful predictor of ventricular electrical instability in the absence of other specific markers, and a promising guide for effective pharmacological therapy.

Adult↗
PubMed1994

The gene for arrhythmogenic right ventricular cardiomyopathy maps to chromosome 14q23-q24.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVD) is a dominantly inherited disorder progressively affecting the myocardium and it is one of the major causes of juvenile sudden death. The chromosomal localization of the disease gene is reported here for the first time. A maximum lod score of 6.04 was obtained at theta = 0 for linkage with the polymorphic marker D14S42 (14q23-q24) in two families, one of which has 82 subjects (19 affected) in four generations. The pre-symptomatic identification of ARVD carriers by linkage analysis in the affected families strongly increases the possibility of prevention of life-threatening complications.

Arrhythmias, Cardiac↗
PubMed1994

Long-term follow-up of patients with single lead VDD stimulation.

The purpose of this study was to assess the long-term results of a single lead VDD pacing system (Phymos MPS) in 85 patients (48 males, 37 females, mean age 74 +/- 9 years). The system, which incorporates two atrial floating electrodes (Phymos 830-S), was implanted for second- or third-degree Mobitz II AV block. The percentage of AV synchronized pacing, the presence of fusion beats due to short AV delay, and the occurrence of supraventricular arrhythmias was evaluated by Holter monitoring at 6-month intervals. Over a mean period of follow-up of 44 months (range 2-56), over 90% of AV synchronized pacing events were noted in 74 patients (87%). The presence of persistent fusion beats was detected in 12 patients (14%). In ten patients the pacemaker was reprogrammed to VVI mode for supraventricular arrhythmias (7 patients, 8.2%) or unsatisfactory atrial sensing (3 patients, 3.5%). One pacemaker was removed for pocket infection and two for battery depletion. These observations support the use of VDD single lead pacing to combine a physiological mode of stimulation with simple implantation techniques.

Aged↗
PubMed1993

Endomyocardial biopsy in right ventricular cardiomyopathy.

Right ventricular cardiomyopathy is characterized by a progressive myocyte loss and fibro-fatty substitution of the right ventricle. The aim of our study was to assess the diagnostic accuracy of right ventricular endomyocardial biopsy. Using an imaging analyser system, histomorphometric parameters of myocytes, interstitium, fibrous tissue and fatty tissue were evaluated on endomyocardial biopsy from 30 patients with arrhythmogenic right ventricular cardiomyopathy, 29 patients with dilated cardiomyopathy and 30 control patients. The percent area of myocytes decreased from 78.10 +/- 7.34 in control to 63.39 +/- 9.22 in dilated cardiomyopathy (P < 0.05) and to 47.28 +/- 15.01 in arrhythmogenic right ventricular cardiomyopathy (P < 0.01). Fibrous tissue increased from 8.10 +/- 3.89 in control to 21.80 +/- 9.29 in dilated cardiomyopathy (P < 0.05) and to 24.60 +/- 11.37 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue varied from 0.33 +/- 1.44 in control and 0.07 +/- 0.31 in dilated cardiomyopathy to 13.30 +/- 17.30 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue was a feature of arrhythmogenic right ventricular cardiomyopathy (67% of patients vs. 6% of control and dilated cardiomyopathy patients). Diagnostic values typifying arrhythmogenic right ventricular cardiomyopathy, obtained by excluding any overlapping between confidence intervals in the three groups, were: myocytes < 44.95%; fibrous tissue > 40.38%, and fatty tissue > 3.21%, with 67% sensitivity and 91.53% specificity for at least one parameter. In conclusion, a significant difference between arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy and control exists in terms of amount of myocytes, fibrous tissue and fatty tissue. Presence of fatty tissue and fibrous tissue exceeding 3.21% and 40.38%, respectively should be considered highly suspect for arrhythmogenic right ventricular cardiomyopathy in right ventricular endomyocardial biopsy.

Adipose Tissue↗
PubMed1993

Heart rate variability in patients with orthotopic heart transplantation: long-term follow-up.

To evaluate heart rate variability (expressed as the standard deviation of RR intervals) within 5 years of follow-up, we studied 20 patients (14 males, 6 females, mean age 44 +/- 12 years) who underwent orthotopic heart transplantation. Six measurements were taken: one in the first 3 weeks after transplantation, and the others once annually, for 5 years. Twenty healthy subjects (mean age 44 +/- 7 years) constituted the control group. Heart rate variability increased significantly in the first 3 years of follow-up (7.2 +/- 1 vs. 11.1 +/- 4, p < 0.001; 11.1 +/- 4 vs. 15.2 +/- 4, p < 0.01; 15.2 +/- 4 vs. 18.9 +/- 5, p < 0.05); in the following years this trend slackened and values did not reach a statistically significant difference (18.9 +/- 5 vs. 21.4 +/- 5; 21.4 +/- 5 vs. 22.5 +/- 5). The mean standard deviation was invariably greater in the control group (63.6 +/- 12). These findings show that sinus rhythm variability in the denervated heart progressively increased over 5 years of follow-up. The absence of presynaptic uptake, which is responsible for adrenergic hypersensitivity to circulating catecholamines and intrinsic cardiac reflexes, does not appear to cause this phenomenon, since these mechanisms are not able to evolve in time after cardiac transplantation. Therefore, an enhanced beta-adrenergic receptors density or affinity to circulating catecholamines or a limited sympathetic reinnervation may be the more probable underlying mechanism.

Electrocardiography, Ambulatory↗
PubMed1993

Heat inactivation of bovine serum used for blockade in immunoenzymatic assay is associated with spurious fall on the titers of anticardiolipin antibodies in primary antiphospholipid syndrome sera.

Anticardiolipin antibodies (ACA) were evaluated using enzyme-linked immunosorbent assay (ELISA) with and without heat inactivation of bovine serum used for plastic surface blockade. Untreated sera samples from primary antiphospholipid syndrome patients (PAS) and healthy blood donors (HBD) were tested. A significant decrease of ACA titers of PAS sera occurred with inactivated bovine serum blockade ELISA when compared with basal ELISA. In HBD sera there was no significant change. Probably, as happens with normal human serum, heating for normal bovine serum produces an increase in ACA titers. This bovine ACA may react with cardiolipin, and when human samples are added, they find antigen sites occupied, resulting in a spurious decrease of ACA titers.

Animals↗
PubMed1993

Right ventricular cardiomyopathy in identical and nonidentical young twins.

We describe the first sets of identical and nonidentical twins with right ventricular cardiomyopathy (RVC). Pair A: A 12-year-old boy was referred because of palpitation and syncope. Clinical and instrument examinations revealed an enlarged and depressed right ventricle (end-diastolic volume = 110 ml/m2; ejection fraction = 44%), spontaneous ventricular tachycardia, and fatty-fibrous infiltrates in the biopsy specimens. His asymptomatic, monozygotic twin showed localized involvement of the right ventricle with isolated, ventricular extrasystoles. Pair B: These 18-year-old nonidentical twin boys showed diffuse right ventricular involvement (end-diastolic volume = 110 ml/m2 and 114 ml/m2; ejection fraction = 30% and 24%, respectively), induction of sustained and nonsustained ventricular tachycardia, respectively, and fibrosis on endomyocardial biopsy. One of the boys died suddenly at rest after documented ventricular fibrillation. These cases support the hypothesis of a genetic etiology with a minor role for genotype and point to the important influence of environmental factors in determining the clinical features of the disease.

Adolescent↗
PubMed1993

Multinucleated hepatocytes induced by rifabutin in rats.

Rifabutin is an antibiotic of the rifamycin class, which is particularly active against mycobacteria, including those that occur in AIDS patients. Because clinical use will include long-term therapy, an extensive battery of long-term toxicity studies was carried out by the oral route, including carcinogenicity studies. An interesting feature was the occurrence of multinucleated hepatocytes (MNHs) in the rat. In some instances, as many as 25 nuclei occurred in a single cell. Light microscopy revealed a large hepatocyte with normal eosinophilic staining. The multiple nuclei stained like those present in the surrounding normal cells. Electron microscopy showed no abnormalities of the nuclei and no cell membranes within the cytoplasm. The customary organelles were present. MNHs were dose- and sex-related, starting from 10 mg/kg/day and being more evident in males. They began to appear after 5 wk of treatment and persisted over long periods of recovery (12 mo), without showing any tendency for cell proliferation. The life-span of MNHs was similar to that of normal hepatocytes. MNHs were present in the carcinogenicity study, but there was no increase in liver tumors. MNHs did not occur in mice or monkeys treated with rifabutin, nor did they occur in response to treatment with rifampin. The effect appears to be specific to the rat.

Animals↗
PubMed1992

A casual spontaneous mutation as possible cause of the familial form of arrhythmogenic right ventricular cardiomyopathy (arrhythmogenic right ventricular dysplasia).

In a family affected by arrhythmogenic right ventricular cardiomyopathy (ARVC) the familial occurrence was investigated. All 14 members of two generations were investigated carefully, and only 2 (father and one son) members were affected. Both subjects had a massive form of the disease with relevant ventricular arrhythmias. Apart from the limitations of having investigated few subjects, this behavior suggests a genetic mutation appearing in the father and transmitted via an autosomal dominant trait.

Adolescent↗