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Biomedical subjects

A Nava

Publications and source records attributed to A Nava.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Effect of heat inactivation and sheep erythrocyte adsorption on the titer of anticardiolipin antibodies in primary antiphospholipid syndrome and healthy blood donors' sera.

The standard enzyme linked immunosorbent assay (ELISA) currently in use for detection of anticardiolipin antibodies (ACA) was used to evaluate the influence of heat inactivation and sheep erythrocyte adsorption on individual optical density (OD) of sera from healthy blood donors or patients with primary antiphospholipid syndrome. Each sample was tested after single or combined maneuvers as follows: adsorbed, adsorbed and inactivated, only inactivated, and compared to basal readings. A significant increase of ACA titers did occur after inactivation of normal sera, but adsorption had no effect. In contrast, neither inactivation nor adsorption changed ACA titer in primary antiphospholipid syndrome sera as a group, although in certain sera there were changes. This observation may suggest the presence in normal serum of a thermolabile factor which modulates ACA binding to its antigen and the reactivity of the anticardiolipin antibodies of the primary antiphospholipid syndrome with sheep erythrocyte membrane phospholipids.

Adsorption↗
PubMed1992

Clinical profile of concealed form of arrhythmogenic right ventricular cardiomyopathy presenting with apparently idiopathic ventricular arrhythmias.

In 24 subjects presenting with apparently idiopathic ventricular arrhythmias, a final diagnosis of arrhythmogenic right ventricular cardiomyopathy was formulated following global evaluation of the clinical, cross-sectional echocardiography and angiographic findings, and the observation of myocardial atrophy with fibrous-fatty substitution in right ventricular endomyocardial biopsy. All patients had good effort tolerance, and a normal cardiac silhouette. Ventricular arrhythmias with a left bundle branch block pattern were present in 23 cases (sustained ventricular tachycardia, nonsustained ventricular tachycardia, ventricular couplets, and ventricular premature complexes); 1 patient experienced an episode of ventricular fibrillation. A nearly constant electrocardiographic feature was T wave negativity in the right precordial leads. Cross-sectional echocardiography and hemodynamic studies showed that right ventricular impairment consisted only of localized structural and dynamic abnormalities; in a few cases the left ventricle was segmentally involved. Familial occurrence was present in 29% of the cases. No case of sudden death was observed during follow-up. These findings confirm that the concealed form of arrhythmogenic right ventricular cardiomyopathy is a cause of so-called "idiopathic" ventricular arrhythmias in subjects with apparently "normal hearts". Echocardiographic and angiographic investigations may lead to the correct diagnosis.

Adolescent↗
PubMed1992

Prolonged cardiac arrest and complete AV block during upright tilt test in young patients with syncope of unknown origin--prognostic and therapeutic implications.

The purpose of this study was to define the history and prognosis of 12 patients (8 males, 4 females) with syncope of unknown origin (5 to 15 episodes), who developed prolonged asystole or complete AV block during the upright tilt test (UTT). The mean age (+/- SD) of the patients was 29 +/- 7.4 years, and all had normal neurological and cardiological findings on evaluation. These patients were selected from a larger group of 92 cases with positive UTT out of a total of 136 subjects who were referred for recurrence of syncope. Neither clinical nor autonomic nervous system evaluation distinguished these 12 patients from those with positive UTT. Following UTT, therapy was initiated and consisted of transdermal scopolamine in four, disopyramide in two, and beta-blockers in four patients. During follow-up (mean, 17 +/- 5.4 months), four patients had recurrences but none experienced episodes of life-threatening syncope. These patients do not show an enhanced risk of sudden death, and drug therapy seems to improve their clinical course. Only long-term follow-up would correctly identify a subgroup at higher risk.

Adult↗
PubMed1990

[Electro-vectorcardiographic study of ventricular extrasystole in arrhythmogenic dysplasia of the right ventricle].

The morphology of ventricular extrasystole (VES) in 46 cases of arrhythmogenic dysplasia of the right ventricle (ADRV) was correlated with the point of origin located by intracavitary mapping. The cases concerned 41 of left bundle-branch block (LBB) with various axes on the frontal plane (FP), 4 of right bundle-branch block (RBB), and 5 of atypical morphology (frontal plane shifted inferiorly and increased R from V1 to V6; on the horizontal plane, clockwise rotation of the loop oriented anteriorly and leftward). There is a good correlation with the site of origin: VESs which were LBB in appearance originated in the right ventricle (apex, septum, infundibulum); VESs which were RBB in appearance originated in the apex of the left ventricle, while the atypical VESs started in the upper posterior septum. A study of morphology may therefore also give an indication of the location of the disease.

Adolescent↗
PubMed1978

[Electrophysiological demonstration of more structures in the atrioventricular node (author's transl)].

Three types of atrioventricular nodal conduction curves, relating A1A2 to H1H2, generated with atrial extrastimulus technique, are known. The first type is smooth, suggesting the homogeneous structure of A-V node. The second type, with abrupt increase in H1H2 response over a critical range of A1A2 coupling intervals, suggests the presence of fast and slow A-V nodal pathways. We have found in five patients the third tipe of A-V conduction curve, giving evidence of an intranodal final common pathway, distal to the fast and slow A-V nodal pathways. The thyrd type of curve enables us to know also some alectrophysiological properties of final common pathway. Indeed we have defined effective and functional refractory periods of fast, slow and final common pathways as far as we can in this type of curve. Paced heart rate variations and atropine medications have led the third type of A-V conduction curve to change into the second type in three cases, into first type in one case. These changes of A-V nodal conduction curves are related to different influence of cardiac cycle lenghts and autonomic nervous system on refractory periods and conduction velocity of the outlined intranodal structures.

Adolescent↗
PubMed1978

[The experience with permanent cardiac pacing at the Surgical Clinic of the University of Padua Medical School (author's transl)].

A computer analysis is reported of the most significant data concerning 1624 pacemaker implantations and 1386 battery replacements. The patients were treated by endocardial stimulation with transvenous electrodes in 91% of the cases; the remainder: 9% received epicardial electrodes. The mode of stimulation was 2189 times "demand", 138 "synchronized" and 683 "asyncronous". Pacers of 13 different brands were used. At the beginning of our experience, the catheter was introduced through the superficial or profunda giugular vein: since 1969 the cephalic vein has been preferred. Epicardial electrodes were implanted via a left thoracotomy but in the most recent years the extrapleural phrenico-pericardial approach has been adopted. In a number of cases external pacemakers have been employed for permanent stimulation. The most common post-operative complications were infection (3.9%), skin erosion (2.2%), catheter rupture (3.5%), electrode dislodgement (1.7%). Such complications are becoming less frequent since 1969, due to technical improvements.

Adolescent↗
PubMed1977

[Reliability of premature atrial stimulation in the study of sinoatrial conduction time (author's transl)].

Premature atrial stimulation was carried out in 32 patients, and for each stimulus the basic cycle (A1A1), test cycle (A1A2), and the return cycle (A2A3) were analyzed. When A2A3 was plotted as the function of A1A2, a biphasic pattern, characterized by a slope phase followed by a "plateau", was observed in 25 subjects. Sinoatrial conduction time (SACT) was calculated using the Strauss method, which assumes that in the plateau A2A3 = A1A1 + SACT. Sinus arrhythmia was also determined in order to evaluate its importance in altering the results of premature atrial stimulation: it should be pointed out that when arrhythmia was marked it was impossible to calculate sinoatrial conduction time. An inverse correlation between A1A1 and the calculated SACT and between A1A1 and A2A3/A1A1 in the plateau was also demonstrated. The reliability of SACT obtained by premature atrial stimulation is discussed in relation to the results obtained and the data found in the literature.

Adolescent↗
PubMed1977

[The atrial stimulation programmed for the research of dual A-V nodal conduction pathways (author's transl)].

Several techniques of premature atrial stimulation were used in a group of 28 not selected patients admitted to electrophysiological investigations of different rhythm troubles. The purpose of this study was the demonstration of dual A-V nodal pathways. The method consisted in the delivery of one or two atrial extrastimuli at every sixth beat, with or without atrial pacing at increasing rate, up to the either atrail or nodal refractory period. Then a curve of intranodal conduction was plotted. The different techniques led us to a curve reproducible in the 89% of the cases. Its main features are the steady increase of the A-H interval, the subsequent sudden "jump" of the same at critical shortening of the coupling stimulation interval and finally a third segment of steady increase until the atrial or nodal refractory period is reached. We believe that this behaviour is common in the man. The significance of the "jump", of the morphology of the curve and their possible relationship with the existence of dual A-V nodal pathways is discussed. Finally the different stimulation techniques are compared.

Adolescent↗
PubMed1976

Multiple lesions of the conduction system in a case of cardiac rhabdomyosarcoma with complex arrhythmias. An anatomic and clinical study.

Anatomic and electrocardiographic correlations in a case of primary cardiac rhabdomyosarcoma are examined. Interatrial and atrioventricular conduction disturbances were associated with multiple lesions involving the alleged internodal pathways, together with atrial-atrioventricular nodal connections. The clinicopathologic findings seem to be consistent with the hypotheses of the functional and morphologic value of Bachmann's fascicle, and of the inherent pathways of interatrial and internodal conduction in health and disease.

Adult↗
PubMed1976

[The right bundle branch blocks with posterior loop (author's transl)].

The AA. have analysed 39 VCG which show terminal slowed down forces definitely directed towards the right and the back. It is presumed that such electrical patterns have to be classified amongst defects which deal with right intraventricular conduction. Both the ECG and UCG test have been classified in groups: some of them simulating BFA, others BFP. An analysis of the different developing ways of the vectorial loops has been made. The AA. think that in some cases the particular direction of the terminal forces could be compatible with an isolated and zonal right conduction defect in the posterior region of the right ventricle. In other cases the coexisting electrical pathology of the left ventricle is likely to be responsible for it. At the end the distinguishing diagnostic criteria of the ECG are discussed.

Adolescent↗