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Biomedical subjects

G Vergara

Publications and source records attributed to G Vergara.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Transvenous bidirectional shock with a triple electrode system: a promising step in the electrical management of ventricular tachyarrhythmias].

The aim of this work is to assess the reliability of transvenous high energy bi-directional shock with a triple electrode system as the initial step in implanting the automatic cardioverter defibrillator by thoracotomy. During the electrophysiological study on 12 patients, 16 different types of sustained ventricular tachycardia were treated with a 25 J bi-directional QRS synchronized shock delivered through a right ventricular apical cathode and 2 anodes, i.e., the superior vena cava-right atrium and skin patch electrode placed just above the left nipple. A Medtronic 6880 catheter, placed in the right ventricular apex, and a cutaneous patch (CRS, 50 cm2 in surface area) were connected by a cable to a Medtronic model 5350 external cardioverter defibrillator. All but one patient had coronary disease with previous myocardial infarction. The mean VT cycle length was 299 msec (min 200, max 380 ms); 5 VT types had left and 2 had right bundle branch block pattern; 9 had a "bizarre" pattern. The tachycardia was interrupted in 14 types; in 1 type (cycle length 360 msec with "bizarre" morphological pattern) ventricular fibrillation was induced by a well synchronized shock; in 1 type (cycle length 200 msec with "bizarre" morphological pattern) a badly synchronized shock induced a sustained ventricular tachycardia with a longer cycle length (360 msec); this was subsequently stopped by another shock. The transvenous high energy bi-directional shock was quite well tolerated by the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Arrhythmologic study of 50 patients with arrhythmogenic disease of the right ventricle: prognostic implications].

UNLABELLED: Arrhythmogenic right ventricular disease is a syndrome which involves a wide spectrum of anatomo-clinical features. It is characterised by different levels of right ventricle anomaly, and by life-threatening "right" hyperkinetic ventricular arrhythmias. Fifty consecutive pts were retrospectively examined at the Arrhythmological Centre in Trento between 1977 and 1988. The results of rigorous arrhythmological, echocardiographic and angiographic criteria showed that all pts were affected by arrhythmogenic right ventricular disease. CASE STUDY: 39/50 (78%) males, 11/50 (22%) females; age 30.6 years (11-78) at the time of the first study. METHODS: clinical history in 50/50 pts, electrocardiogram in 50/50 pts, Holter monitoring in 50/50 pts, ergometric test in 49/50 pts, non-invasive analysis using signal-averaging QRS in 17/50 pts, 2D echocardiogram in 50/50 pts, angiography in 38/50 pts, electrophysiological endocavitary study in 35/50 pts. RESULTS: familial 2/50 (4%); 1/50 (2%) was in class II NYHA; first arrhythmia at 24.6 years (8-60); most severe arrhythmia at 27.7 years (9-74). Forty-three out of fifty patients (86%) were symptomatic for arrhythmias: 28/50 (56%) as a result of stress; 20/50 (40%) had life-threatening symptoms; 6/50 (12%) had aborted sudden death. Arrhythmogenic right ventricular disease was "localized" in 42/50 (84%) and "diffused" in 8/50 (16%) and was associated with anomalies of the left ventricle in 30/50 (60%). Electrocardiogram showed: right bundle branch block in 10/50 (20%), negative T wave on the right precordial leads in 19/50 (38%), delayed ventricular potentials in 4/17 (23.5%). Using the electrocardiogram, Holter monitoring and electrophysiological endocavitary study the following were documented: a) clinical ventricular tachycardia in 40/50 (80%): non-sustained ventricular tachycardia in 10/50 (20%), sustained ventricular tachycardia in 30/50 (60%); b) electrically induced ventricular tachycardia in 26/35 (74.2%): non-sustained ventricular tachycardia in 8/35 (22.8%), sustained ventricular tachycardia in 18/35 (51.4%) (clinical sustained ventricular tachycardia in 18/18); c) multiform ventricular tachycardia in 12/50 (24%) (diffused arrhythmogenic right ventricular disease in 3/12 and associated anomalies of the left ventricle in 11/12); d) pleomorphic sustained ventricular tachycardia in 9/30 (30%) (diffused arrhythmogenic right ventricular disease in 2/9, and associated anomalies of the left ventricle in 8/9). Forty-two out of fifty patients (84%) underwent antiarrhythmic treatment. When the study was carried out 6.6 years (1 month-22 years) had passed since the first symptom; follow-up was 2.1 years (1 month-11 years) while the interval between the first symptom and the last check-up was 8.4 years (1-30 years); 2/50 dropped out and 2/50 died suddenly.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1988

Induction of supraventricular tachyarrhythmia at rest and during exercise with transoesophageal atrial pacing in the electrophysiological evaluation of asymptomatic athletes with Wolff-Parkinson-White syndrome.

Even today there is controversy as regards the best approach to asymptomatic or slightly symptomatic athletes with the WPW syndrome as regards fitness for sports activity, especially in some countries where the doctor is responsible for certifying sports fitness. This study concerns 84 asymptomatic or slightly symptomatic athletes (66 males, 18 females, mean age 21.7 years, range 12-44 years) who underwent a stimulation protocol the end-point of which was the induction of atrial fibrillation (or, if not possible, atrial tachyarrhythmia) in the basal state and during bicycle stress test with transesophageal atrial pacing. The 81 athletes in whom the end-point was reached were divided into two groups: Group I includes the 32 athletes with the shortest R-R interval between pre-excited beats less than or equal to 240 ms in the basal state and/or less than or equal to 210 ms during bicycle ergometer test, Group II includes the other 49 patients. The evaluation during exercise was not carried out in four athletes because of serious haemodynamic compromise due to the arrhythmia induced in the basal state. Only 21/32 athletes would have been included in Group I if only evaluated in the basal state. In 30/81 athletes (37%), there was discrepancy between the result of stimulation and the result of the usual non-invasive evaluation (Holter monitoring, ergometric stress test, ajmaline test). On average, 40 min are required for the performance of the study protocol except when the induced arrhythmia lasts more than 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Flecainide and encainide.

Flecainide and encainide (class IC) are presently under clinical evaluation in Italy. They prolong the duration of the QRS but not the period of ventricular repolarisation: the prolongation of QT is due solely to the prolongation of the Q-J. Flecainide and encainide are extremely powerful and are suitable for the treatment of reciprocating supraventricular paroxysmal tachycardia and of persistent reciprocating tachycardia, the prophylaxis of WPW atrial fibrillation including cases with a short anterograde refractory period of the anomalous pathway and the treatment of ventricular ectopic beats and ventricular tachycardia. Both drugs are probably effective for the treatment of atrial fibrillation. However, in the case of atrial flutter they are of little effect of sinus rhythm cardioversion; on the other hand they significantly prolong the duration of the A-A interval, with variable results on ventricular rate. Flecainide and encainide have 'parodoxical' arrhythmogenic effects, related to administration dosages, severity of the arrhythmia and seriousness of cardiopathy. Encainide shows peculiar pharmacokinetics due to hepatic oxidating metabolisation and to production of metabolites; among these the O-demethylencainide and the 3-methoxy-O-demethylencainide have an antiarrhythmic activity, which is probably more important than the encainide parent and is longer-lasting. There are 'extensive', 'poor' and 'non-metaboliser' subjects. This results in wide pharmacokinetic inter- and intraindividual variability which must be taken into account during clinical treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Anilides↗
PubMed1987

[Value and limitations of 2-dimensional echocardiography in the identification of arrhythmogenic right ventricular dysplasia].

The aim of this study was to evaluate the value and limitations of Cross-sectional Echocardiography (CSE) in the diagnosis of Arrhythmogenic right ventricular dysplasia (ARVD). Diagnosis was based on accepted clinical, electrocardiographic, electrophysiologic and angiographic criteria. CSE criteria for the diagnosis are segmental right ventricular wall motion abnormalities of unknown cause, usually associated with localized or diffuse dilatation of right ventricular (RV) chamber and with the presence of localized anomalies consisting of sacculation or bulging of RV wall. Comparison of CSE and RV angiographic findings was performed in 8 patients with ARVD (6 men and 2 women, aged 10 to 37 years, mean 28 years). CSE and angiography compared closely when diffuse RV enlargement and wall motion abnormalities were identified by both techniques. Bulging and sacculation of the RV wall at CSE predicted the presence of similar lesions at angiography, but agreement for specific location was poor and, in addition, CSE showed low sensitivity in their detection. The inherent different information provided by the two methods added to the subjectivity of the qualitative analysis probably accounts for the inconsistencies. Therefore in patients with diagnosed ARVD RV enlargement, otherwise unexplained, associated with wall motion abnormalities and localized anomalies at CSE strongly supports the diagnosis and avoids the need for angiography. By other hand, in patients with high clinical suspicion of ARVD a negative CSE study can not exclude the diagnosis and angiography should be indicated.

Adolescent↗
PubMed1986

[Electrophysiologic evaluation of athletes with Wolff-Parkinson-White syndrome: induction of supraventricular arrhythmia at rest and under exertion with transesophageal atrial electrostimulation].

The most suitable approach to the athletes with WPW is controversial. Therefore 66 symptom-free athletes with WPW and without heart disease (53 M, 13 F, mean age 21.98 yrs, min 12--max 44) underwent a study protocol whose end-point was the induction of supraventricular tachyarrhythmia, i.e. atrial fibrillation or, if not possible, atrial flutter or atrial tachycardia at rest and during ergometric stress test. The athletes with shortest R-R interval between preexcited beats less than or equal to 240 ms at rest and/or less than or equal to 210 ms during exercise were judged as being at risk i.e. no fit for sport activity. The end-point was reached in 64/66 athletes (in 62 atrial fibrillation). In 4 athletes with life threatening arrhythmia induced at rest the evaluation during exercise was not performed. According to the evaluation at rest we were able to identify only 18 athletes (28.1%) as being at risk, while according to the complete study protocol 26 athletes (40.6%) were judged as such. In 23/64 athletes (36%) this judgement was discordant with the usual non invasive evaluation (i.e. Holter monitoring, ergometric stress test, ajmaline test). During induced atrial fibrillation no significant difference, was found between the percentage of preexcited beats at rest and during exercise. On the average, 40 min. are required for performance of this study protocol (if the induced arrhythmia lasts less than 5 min.). According to our results we conclude: a) the non invasive assessment of the WPW athletes is unsatisfactory; b) the induction of atrial fibrillation during exercise gives a remarkable increase of the diagnostic power with respect to the assessment only at rest; c) since it is simple to perform and not expensive (in time, staff and cost) and because of its high diagnostic yield, we regard this protocol as fundamental for the electrophysiological evaluation of WPW athletes and also suitable for systematic study of WPW patients.

Adolescent↗
PubMed1985

[Ventricular hyperkinetic arrhythmias and circulatory arrest in idiopathic isolated complete atrioventricular block. Description of a clinical case].

Here we report on the case of a patient with idiopathic complete AV block and ventricular ectopic beats in basal state. The patient had been asymptomatic until the age of 50 and then suddenly began to suffer from relapsing episodes of syncope, related to "Torsade de Pointe" and Ventricular Fibrillation (hypokalaemia was present at the same time). We deal with the prognostic significance of ventricular ectopic beats and we make the hypothesis that hyperkinetic ventricular arrhythmias play a role in the origin of the symptoms of patients with congenital or idiopathic complete AV block. Finally, we discuss the limits of the therapeutic effectiveness of permanent pacing in these cases.

Cardiac Pacing, Artificial↗
PubMed1985

[Sustained ventricular tachycardia in postinfarct ischemic heart disease: spontaneous polymorphism. Clinical, therapeutic and prognostic aspects].

UNLABELLED: Spontaneous Polymorphism (SP) is present when at least two episodes of Sustained Ventricular Tachycardia (SVT) occur spontaneously in the same patient (pt) with different bundle branch block pattern or with shifting of QRS axis by greater than or equal to 90 in the various episodes. We undertook this study in order to investigate the clinical significance of SP in SVT as well as therapeutic and prognostic implications. MATERIAL AND METHODS. From our global pts populations we chose those with SVT in chronic ischemic heart disease (CIHD) with previous myocardial infarction (PMI), they had to be already studied by electrophysiologic technique (EES). The pts were divided into two groups (Gr.): Gr. I: 13 SP pts (12 M, 1 F, mean age 57.5 +/- 13; mean follow-up 19.2 +/- 11 months); Gr. II: 15 no SP pts (14 M, 1 F, mean age 60 +/- 10; mean follow-up 9.9 +/- 13 months). RESULTS: The two Gr. are comparable in terms of symptoms, exercise tolerance, infarct site, intraventricular conduction disturbances (61.5% and 66.6% respectively), ventricular wells kinetics (38.4% and 26.6% respectively) and time interval between acute myocardial infarction the first episode of SVT (7.58 +/- 6.02 and 8.27 +/- 6.57 years respectively). 8 of the 10 alive Gr. I pts have been treated with Amiodarone (A) (2800-4200 mg/wk). All 9 alive Gr. II pts are on A (1400-4200 mg/wk). A serum level in 7 Gr. I pts was 1.7 +/- 0.65 mcg/ml and 1.61 +/- 0.67 in 5 Gr. II pts. 3/13 Gr. I pts died: 2 for sudden death (15.3%), 6/15 Gr. II pts died: 4 suffered sudden death (26.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Sustained ventricular tachycardia: low-energy transcatheter internal cardioversion. Efficacy, reliability and tolerance in comparison with ventricular burst].

The aim of this study is to evaluate the efficacy, reliability and patient tolerance of low-energy transcatheter intracardiac cardioversion in the treatment of Sustained Ventricular Tachycardia (VT), and to compare this method to ventricular burst. For this purpose 11 patients (pts) (10 M, 1 F, mean age 50.1 yrs, range 24-72) with 18 different types of VT (17 induced during Endocavitary Electrophysiological Study (EES), 1 "clinical"), who all underwent EES all but 1 with organic heart disease, were first treated by transcatheter intracardiac cardioversion and then, if possible, with ventricular burst at 125%-150% of VT rate. The Medtronic Cardioverter 5350 and the Medtronic catheter 6880 were used. The following results were obtained: transcatheter intracardiac cardioversion terminated 9/18 types of VT (8 types at least 3 times) in 6 pts. Cardioversion threshold was on average 1.31 J (range: 0.14-5). Transcatheter intracardiac cardioversion failed to terminate 9/18 types of VT (in 5 pts); VT acceleration or ventricular fibrillation occurred in 6/9 types. The mean cycle length of successfully cardioverted VT (382 +/- 61 msec.) was significantly longer (p = 0.05) than that of not successfully cardioverted VT (284 +/- 83 msec.) and of the VT in whom an acceleration or a degeneration into ventricular fibrillation was observed (240 +/- 55 msec.). In 4 pts it was necessary to use external DC shock and in 4 supraventricular hyperkinetic arrhythmia was induced. All pts complained of considerable discomfort at shocks greater than or equal to 0.5 J. In all the 7 types of successfully cardioverted VT as well as in 3 out of the 4 types of not successfully cardioverted VT in which it was possible to test ventricular burst, this latter proved to be effective. These results indicate that: the efficacy of transcatheter intracardiac cardioversion is not great at least in our pts (50%); moreover, the transcatheter intracardiac cardioversion is affected by a high incidence of acceleration of VT and degeneration into ventricular fibrillation (33.3%) and by the induction of supraventricular hyperkinetic arrhythmia (22.2%). Patient discomfort appears to be a major limitation to transcatheter intracardiac cardioversion. The VT cycle length is determinant for the success of the transcatheter intracardiac cardioversion and for the induction either of an acceleration of VT or of a degeneration into ventricular fibrillation (which are observed only in VT with cycle length less than or equal to 300 msec.).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

[Clinico-electrophysiologic relations in isolated complete atrioventricular block, congenital or idiopathic].

Congenital or idiopathic complete A-V block with no detectable heart disease may be complicated by near syncope, syncope or sudden death. The proposed predictive "risk factors" of these events have not proved sufficiently reliable so far. This study was undertaken in order to re-evaluate the correlation between symptoms and clinical and electrophysiological data with particular regard to the junctional recovery time in 10 patients (4 M; 6 F; mean age 24.4 +/- 9.6 at our first observation) with congenital or idiopathic complete A-V block. Patients were divided into 2 groups: group A (3 M; 3 F; mean age 27.8 +/- 10.6 at our first observation) with patients who complained of vertigo, near syncope or syncope before our study; group B (1 M; 3 F; mean age 19.2 +/- 4.1 at first observation) without cardiovascular symptoms before our study. In group A, Holter monitoring revealed periods of asystole longer than 3000 ms in 2, and ectopic ventricular arrhythmias mainly during effort in 2; ergometric stress test performed in 3 patients demonstrated ectopic ventricular arrhythmias in 2 (those who had ectopic ventricular arrhythmias at rest). In all patients the site of the block was suprahisian (demonstrated by electrophysiologic endocavitary study) with a normal H-V interval; mean junctional recovery time was 4.600 +/- 1.620 ms and corrected junctional recovery time was 3.088 +/- 1.500. Four patients had vertigo during the electrophysiologic endocavitary study. After Atropine 0.02 mg/Kg i.v. junctional recovery time and corrected junctional recovery time decreased respectively to 1052 +/- 238 and 166 +/- 38 ms (the measurement was made in 5 patients). In group B Holter monitoring revealed periods of asystole longer than 3000 ms in 1 case. All patients had ectopic ventricular arrhythmias, confirmed by the stress test. In this group too, the block was suprahisian (electrophysiologic endocavitary study) with normal H-V. Mean junctional recovery time was 5162 +/- 2408 ms; and corrected junctional recovery time 3687 +/- 2202. Two patients complained of dizziness during the electrophysiologic endocavitary study. After Atropine 0.02 mg/Kg i.v., junctional recovery time and corrected junctional recovery time decreased respectively to 1300 +/- 356 and 260 +/- 145 ms. Four group A and 1 group B patients received a permanent pacemaker and have remained asymptomatic since.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗