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Biomedical subjects

A Nava

Publications and source records attributed to A Nava.

At least 127 records · Page 7Linked to original sources
PubMed1987

A polymorphic form of familial arrhythmogenic right ventricular dysplasia.

Thirty-two members of a family were studied. Three of them died in their youth and had evidence of arrhythmogenic right ventricular (RV) dysplasia. The other 29 members underwent clinical examination, electrocardiography, chest x-ray and M-mode and 2-dimensional echocardiography. Fourteen patients found to have structural abnormalities of the right ventricle underwent 24-hour ambulatory electrocardiographic recording and symptom-limited bicycle stress testing. Hemodynamic and angiographic studies were performed in 6 of these patients. In this family the arrhythmogenic RV dysplasia showed a wide variation of abnormalities, ranging from mild, local alterations to generalized involvement of the right ventricle. The patients were separated into 3 groups on the basis of both the clinical profile and noninvasive/invasive studies: 3 subjects who died suddenly; 3 subjects who had severe ventricular arrhythmias; and 8 subjects in whom RV impairment was not associated with any significant arrhythmias. There was no close relation between the severity of the RV abnormality and presence of ventricular arrhythmias. The variability of the RV abnormality and the high prevalence of this condition in this family is consistent with a genetic pattern of autosomal dominance with incomplete penetrance.

Adolescent↗
PubMed1987

[Atrial desynchronization induced by Valsalva's maneuver in a patient with reciprocating supraventricular tachycardia and Wolff-Parkinson-White syndrome].

A 22 years old man with ventricular preexcitation syndrome due to a left accessory pathway, was admitted because of orthodromic reciprocating tachycardia, 205 bpm in frequency. The patient was invited to perform a Valsalva Maneuvre, and at its ending, the tachycardia degenerated into atrial fibrillation (AF) associated with high ventricular rate, reverted to sinus rhythm by D.C. shock. The electrophysiologic study documented a left lateral by pass tract, with an anterograde refractory period of 230 msec. AF was inducible and had a minimal RR interval of 220 msec. Vagal stimulation, induced at the end of Valsalva maneuvre, probably caused dispersion of atrial refractorines and intraatrial reentry, converting the orthodromic tachycardia into atrial fibrillation.

Adult↗
PubMed1986

Rhythm and conduction disturbances in isolated, congenitally corrected transposition of the great arteries.

The incidence and types of rhythm and conduction disturbances in 11 male and 6 female patients with congenitally corrected transposition of the great arteries and no other intrinsic complicating anomalies were studied. Patient age ranged from 5 to 54 years; follow-up ranged from 5 to 37 years. Surface electrocardiograms were recorded in each patient; 15 also underwent 24-hour Holter monitoring and 10 underwent electrophysiologic study. The conduction system of a 54-year-old woman who died suddenly, with complete atrioventricular (AV) block since age 30 years, was studied by serial histologic sections. Fifteen patients were asymptomatic and 2 reported repeated episodes of palpitation since childhood. Ten patients presented with a normal PR interval and 2 with first-degree AV block (12%). Five patients had complete AV block (29%), but none had had it at birth; first- and second-degree AV block preceded complete AV block in 2 patients. The morphologic pattern and duration of QRS suggested a junctional rhythm in 4 patients and an idioventricular pacemaker in 1 patient. Electrophysiologic studies confirmed that the complete AV block site was supra-Hisian in 2 patients and proximal to the His bundle bifurcation in 1 patient. However, histologic investigation disclosed fibrosis and disruption of the proximal nonbifurcating His bundle in the patient who died suddenly. In 2 patients with recurrent supraventricular tachycardia, electrophysiologic studies suggested reentry through James fibers (or dual AV nodal pathway) in 1 and the presence of a left lateral accessory AV pathway in the other. Holter monitoring showed a high incidence of ventricular arrhythmias.

Adolescent↗
PubMed1986

Fatal paroxysmal supraventricular tachycardia in an infant.

A 37-day-old infant, without associated congenital anomalies, died following a 48-hour episode of supraventricular tachycardia. The histopathologic findings of nodoventricular and fasciculoventricular Mahaim's fibers in a setting of persistent fetal dispersion were consistent with an anatomic substrate for a reentry circuit at the specialized A-V junction.

Electrocardiography↗
PubMed1986

[Vectorcardiographic analysis of late potentials].

We analyzed by high amplification vectorcardiography the morphology of the QRS ending loop and the ST segment of patients with previously recorded Lown 4A, 4B ventricular arrhythmias and the healthy subject. Eight patients were affected by ischemic heart disease and 7 by arrhythmogenic right ventricular dysplasia. All had some irregularities at the end of the QRS or in the ST segment, on the standard ECG. The VCG showed one or more of these three morphologies: complete or incomplete ring, rapidly inscripted isodi-triphasic potentials, sinusoidal irregularities. In the 20 healthy subjects, the loop corresponding to the last 30 msec of the QRS, till the end of the afferent portion of T, was regular, without any particular morphology. We think that these aspects could be related to delayed fragmentation of the ventricular depolarization.

Arrhythmias, Cardiac↗
PubMed1986

[Tachycardia and ventricular fibrillation in the arrhythmogenic right ventricle (arrhythmogenic dysplasia of the right ventricle). Clinical and electrocardiographic spectrum].

In this paper we report the arrhythmias recorded on basal ECG, on Holter monitoring or on exercise test, in 32 pts affected by arrhythmogenic right ventricle (ARV). A sustained ventricular tachycardia (VT) was present in 11 pts a non sustained VT in 15 pts, a slow VT in 2 pts, a ventricular fibrillation (VF) in 3 pts and both sustained VT and VF in 1 pt. All but 1 case of sustained VT showed a LBBB like pattern. The heart rate during VT ranged between 170 and 280 beats/min. The frontal axis of the VT showed a wide range of deviation. Among non sustained VT, 9 cases had LBBB like pattern and 6 cases had polymorphic configuration. The 2 cases of slow VT showed LBBB like pattern with right axis deviation. A comparison between ventricular arrhythmias and RV impairment was made. The data obtained suggest that the effort plays an important role in the induction of VT in pts with localized RV impairment. In conclusion a wide spectrum of ventricular tachyarrhythmias is present in the ARV. Probably the RV "arrhythmogenic" zones and the electrophysiological mechanism causing the arrhythmias are various.

Adolescent↗
PubMed1984

Dysplasia of the atrioventricular valves associated with conduction system anomalies.

Clinical, vectorcardiographic, and echocardiographic data from two siblings with atrial septal defects and dysplasia of the mitral and tricuspid valves are reported. Vectorcardiograms showed that both siblings had abnormal ventricular activation with initial electrical forces directed posteriorly. One sibling died after surgery, and necropsy showed incomplete differentiation of the leaflets and tensor apparatus producing anomalies resembling "mitral arcade." Serial histological examination of the conducting tissue showed that the atrioventricular node was located on the left side of the atrial septum, that the central fibrous body and the membranous septum were hypoplastic, and that an accessory nodoventricular pathway originating in the compact node joined the left side of the ventricular septum. This accessory pathway was probably the cause of the unusual ventricular activation. Dysplasia of the mitral and tricuspid valves together with hypoplasia of the central fibrous body and the presence of accessory pathways are probably part of a malformative complex caused by incomplete differentiation of both the cardiac atrioventricular valves and the junctional area.

Child↗