PubMed Health⌕ Search

Biomedical subjects

J L Tonet

Publications and source records attributed to J L Tonet.

At least 19 recordsLinked to original sources
PubMed1990

[Effect on atrioventricular conduction of a new calcium antagonist: lacidipine. Evaluation by the Holter method].

The modification of AV conduction induced by 4 mg b.i.d. of lacidipine (L), a new calcium antagonist, was assessed by studying the changes in ventricular rhythm in 10 patients with stable chronic atrial fibrillation (mean age 71 +/- 15) by daily Holter recordings. The study was single blind versus placebo (P), nifedipine (N) 10 mg b.i.d. and for five patients diltiazem (D) 120 mg b.i.d. Five or seven consecutive 24 hours Holter were recorded in the following order: P, P, N or L, P, N or L, D, D. For each hour, an RR histogram was drawn and the 10 per cent and 90 per cent values of the cumulative cycle length curve were computed, as were the total number of QRS, and the mean value of RR intervals. The correlation coefficient between the number of QRS from the same hour on different days, the Student t test between the mean hourly RR interval values and the comparison between the histograms did not demonstrate a significant difference between the placebo, the nifedipine and the lacidipine periods. The only significant changes were induced by diltiazem (p less than 0.01), with a significant prolongation of the RR intervals. This suggests that lacidipine, like nifedipine, has no effect on AV conduction.

Aged↗
PubMed1989

[Treatment of ventricular tachycardia using endocavitary fulguration. 5 years' experience with 53 cases].

53 patients, between the ages of 14 and 76 years, presented a ventricular tachycardia which was treated by the fulguration method. 19 resulted from a complication of an old myocardial infarction, 15 from a right arrhythmogenic ventricular dysplasia, 8 from a dilated myocardiopathy. 10 patients presented idiopathic tachycardias: 3 originated in the infundibulum of the right ventricule and 7 from the left ventricle. One case originated from a surgical scar of the infundibulum. These tachycardias were continuous or occurred daily in half of the cases, or presented monthly recurrences. 1 to 17 shocks were delivered at each session, 143 on the right, 112 on the left and 2 transseptal. Four patients died from haemodynamic deterioration prior to the shock. The other 49 patients are considered as clinical successes. Three died within the first three months of low cardiac output without any recurrence of the tachycardia. 26 did not longer present any recurrent tachycardia and were not given any preventive anti-arrhythmic treatment. 19 developed recurrence or could be triggered off again, but the anti-arrhythmic medications which were ineffective, become effective. One female patient again developed slavos of ventricular tachycardia after a few months. Seven patients died 4 to 18 months after fulguration, and three presented a sudden death. They belong to the group with medically treated recurrences. This technique is a major factor in the therapeutic strategy of ventricular tachycardias, either used alone or associated with a pharmacological treatment.

Adolescent↗
PubMed1989

Electrode catheter ablation of resistant ventricular tachycardia in arrhythmogenic right ventricular dysplasia: experience of 13 patients with a mean follow-up of 45 months.

Electrode catheter ablation (fulguration) is a new technique for the treatment of ventricular tachycardia resistant to medical treatment. It proved effective in our hands in a series of 65 cases of ventricular tachycardia of varied origin. This paper reports the early results in a subgroup of 13 patients suffering from arrhythmogenic right ventricular dysplasia in whom shocks ranging from 160 to 280J, single or multiple, in one or up to three sessions were delivered. In the 11 patients surviving the DC ablation procedure single or multiple monomorphic sustained VT was brought under control. However, four patients (36%) required therapeutic antiarrhythmic treatment following the fulguration therapy. During the learning phase one case of death was related to poor catheter selection and the other to poor protocol. The post-mortem study of the effect of shocks depends on the anatomical structure to which the shocks have been delivered.

Adult↗
PubMed1989

Clinical experience with fulguration and antiarrhythmic therapy for the treatment of ventricular tachycardia. Long-term follow-up of 43 patients.

Forty-three patients (mean age, 45 +/- 18 years) with drug-refractory VT of varied etiologies, including 15 cases occurring after chronic myocardial infarction, underwent fulguration procedures. With a mean follow-up of 29 +/- 12 months (range, 9 to 55 months), after one to four sessions, VT had been controlled without a need for antiarrhythmic drugs in 22 (56 percent) of the 39 patients surviving the perioperative period and was controlled in 17 patients (44 percent) with the help of drugs. No malignant arrhythmias were observed following fulguration. There were five early deaths, four deaths related to the procedure, and eight late deaths, but no death was thought to be related to the endocardial shock itself. Thus, fulguration appears to be a valuable adjunct to the treatment of drug-resistant VT.

Adolescent↗
PubMed1988

Identification and catheter ablation of a zone of slow conduction in the reentrant circuit of ventricular tachycardia in humans.

Three patients who had incessant ventricular tachycardia and in whom a zone of slow conduction was identified are presented. Each patient's tachycardia was refractory to multiple antiarrhythmic drugs and was being treated with amiodarone at the time of the electrophysiologic study. The ventricular tachycardia cycle length was 500 to 580 ms. In Patients 1 and 2, a single site at the posterolateral wall or low septum in the left ventricle was identified at which overdrive pacing during ventricular tachycardia resulted in ventricular capture with a stimulus to QRS interval of 280 to 400 ms and with little or no change in the configuration of the QRS complexes during pacing as compared with during ventricular tachycardia. In Patient 3, the same phenomenon was observed at two areas in the left ventricle: at the inferior wall, overdrive pacing during ventricular tachycardia resulted in a stimulus to QRS interval of 440 to 470 ms, whereas at the posterolateral wall, the stimulus to QRS interval was 320 to 360 ms. Transcatheter shocks of 100 to 240 J delivered at the pacing sites have been successful in preventing recurrences of ventricular tachycardia over a follow-up period of 10 to 11 months. These observations may be explained by the pacing site being located within a reentrant circuit in a zone of slow conduction bounded by inexcitable tissue between the pacing site and the exit site of the reentrant circuit. In Patient 3, the variable stimulus to QRS intervals are explained by variable proximity of the pacing sites within the slow conduction zone to the exit site of the reentrant circuit.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Techniques and methods for catheter endocardial fulguration.

Fulguration is a new and promising technique for the treatment of cardiac arrhythmias. This paper discusses the methods and equipment used at Jean Rostand Hospital for invasive experimental research related to fulguration. The importance of catheter testing and selection is demonstrated. The most important features of the measurement techniques for both His bundle and ventricular tachycardia recordings are described. The main components of the protocols for fulguration and early post-operative surveillance are reported. The ODAM Fulgucor is used, augmented by the incorporation of additional pieces of equipment to allow monitoring of current and voltage curves. An electromechanical relay allows for automatic switching from the recording amplifier to the energy source. The video system used includes recording of the image of the last fluoroscopic event with a character generator and an electronic pointer superimposed (when necessary). Computer programs for appropriate timing of predominant events have been developed.

Arrhythmias, Cardiac↗
PubMed1988

[Long-term course of conduction disorders in 97 patients with an HV interval superior or equal to 70 milliseconds].

The natural history of disorders of conduction is imperfectly known. The presence of an HV interval of 70 milliseconds or more, which is regarded as pathological, usually results in pacemaker implantation. In this study the course of symptoms and disorders of conduction was investigated in 97 patients with an HV interval of 70 ms or more, and therefore equipped with a pacemaker, followed up for a mean period of 26.5 +/- 19.5 months. Among these 97 patients, 65 had presented with one or several syncopes, 14 had experienced feelings of faintness and 18 were asymptomatic. Among patients with symptoms, these totally disappeared in 63 and became milder in the remaining 12 patients. Complete and permanent AV block was observed in 11 patients. The actuarial incidence of complete permanent AV block was about 5 p. 100 per annum until 4 years. The only predictive parameter for such a course was the occurrence of a second degree type 2 or a third degree paroxysmal block prior to pacemaker implantation (significantly associated with the absence of symptoms).

Adult↗
PubMed1988

[Endocavitary fulguration in the treatment of cardiac arrhythmia].

Fulguration of the heart cavities seems currently to be a technique of increasing value in the treatment of untractable arrhythmias, of supraventricular junctional or ventricular origin. This study represents the evaluation of our experience with 64 patients, maximum follow-up is 54 months and the minimum follow-up is 7 months. Although the results are quite satisfactory in the fulguration of the bundle of his and in the fulguration of the arrhythmic site inducing ventricular tachycardia, these results are inferior in the Wolff-Parkinson-White syndrome in which fulguration of the coronary sinus seems contraindicated al filter (LEM type), resulting in the death of the patient. It is a true, early (1st week) migration after accurate positioning, opposite L4, and not an incident of insertion.

Adolescent↗
PubMed1988

[Sinocarotid hypersensitivity].

Hypersensitivity of the carotid sinus corresponds to a ventricular pause equal to or exceeding 3 seconds and/or a blood pressure drop equal to or exceeding 50 mmHg, induced by massage of the carotid sinus (MCS). MCS remains the diagnostic method of these two syndromes: cardio-inhibitor/vasodepressor. It must be performed systematically during the work-up of transient consciousness disorders since it is not unusual that hypersensitivity of the carotid sinus may cause cardiac syncopes. In addition, hypersensitivity of the carotid sinus is often associated with sinus dysfunction and atrioventricular conduction disorders. In the case of hypersensitivity of the carotid sinus with syncope secondary to a pure or dominant cardio-inhibiting response, heart stimulation with a dual-chamber pacemaker is probably the best treatment. In cases of hypersensitivity of the carotid sinus without syncope, therapeutic abstention is commonly accepted.

Arrhythmias, Cardiac↗
PubMed1987

Treatment of resistant ventricular tachycardia by endocavitary fulguration associated with anti-arrhythmic therapy.

Endocavitary fulgurations were practised in 26 cases of high risk ventricular tachycardia (VT) for which antiarrhythmics including amiodarone and class I antiarrhythmic agents given alone or in combination proved ineffectiveness. Permanent VT was present in nine patients at the time of the fulguration session: three were moribund, and two were unconscious. Included in the series were 10 cases of arrhythmogenic right ventricular dysplasia, nine patients had chronic VT several months after myocardial infarction, four had a non obstructive cardiomyopathy, two were idiopathic and one came after repair of the right ventricular outflow tract. Fulguration succeeded in preventing VT in the 22 patients who survived the initial period of treatment in association with therapeutic antiarrhythmics, in eight cases. Three of the four early deaths were probably related to imperfections in the technique. Two late deaths were due to spontaneous evolution of the disease. The follow-up period ranges from a minimum of 15 to a maximum of 34 months, with an average follow-up of nearly two years. The success rate of fulguration alone or for patients receiving prophylactic antiarrhythmic drugs is 90%. Ten patients required two sessions or more before VT was brought under control.

Adolescent↗
PubMed1987

[Efficacy criteria in the fulguration of the bundle of His].

The authors have endeavoured to determine which of the parameters commonly used for His bundle ablation are likely to predict that ablation will be effective in altering the atrioventricular (AV) conduction system durability. His bundle ablation was performed in 18 patients (9 men, 9 women; mean age 47 years) presenting with supraventricular tachycardia refractory to all medical treatments. A total of 29 shocks were delivered with an Odam fulgurator, using a distal electrode connected to the positive pole of a selected catheter. Fifteen shocks were effective, resulting in a complete and permanent AV block (group I); the remaining 14 shocks failed to modify permanently the AV conduction system (group II). The parameters which differed between these two groups were the amplitude and the stability of the His bundle potential, the energy per kg bodyweight delivered with the shock and the possibility to shock the potential with the greatest amplitude in case of instability. A discriminant linear analysis showed that 3 interrelated criteria could be used to classify 83% of the shocks into one or the other group. In order of importance these criteria were: (1) amplitude of the His bundle potential; (2)energy delivered per kg bodyweight, and (3) stability of the potential. The corresponding discriminant values for successful results were more than 300 mV for parameter 1, more than 3 J/kg bodyweight for parameter 2 and very good stability of His bundle potential.

Adult↗
PubMed1986

[Endocavitary fulguration in the treatment of ventricular tachycardia complicating myocardial infarction].

Endocardial catheter fulguration of ventricular tachycardia consists of sending a defibrillating shock to the tip of an endocavitary catheter lying near the site of origin of the tachycardia. The shock may modify the arrhythmogenic substrate and prevent relapses. We have used this method in 9 cases of post-infarction chronic ventricular tachycardia resistant to drug therapy, and the patients were be followed up for more than 2 years. The results were sometimes life-saving, even in cases with badly damaged myocardium. The electric shock did not significantly alter the myocardium but modified the arrythmogenic substrate enough to prevent long-term relapses. When insufficiently effective, endocardial catheter fulguration can be repeated without problems. Used alone or combined with antiarrhythmic drugs, it opens prospects of new radical therapeutic approaches.

Adult↗
PubMed1986

[Treatment of resistant ventricular tachycardia with endocavitary ablation combined with anti-arrhythmia agents].

Catheter ablation was used in 26 consecutive cases of high risk ventricular tachycardia (VT) resistant to antiarrhythmic therapy. Seven patients were in permanent VT at the time of catheter ablation, three of them were moribund. There were 10 cases of arrhythmogenic right ventricular dysplasia, 9 cases of VT complicating chronic myocardial infarction, 4 cases of dilated cardiomyopathy, 2 cases of idiopathic VT and one congenital cardiac malformation. Ten patients required 2 or more sessions of catheter ablation to treat their arrhythmia. Three of the 4 early deaths (less than 1 month) were due to technical problems. Combined with antiarrhythmic drugs in 8 cases, catheter ablation brought the VT under control in the 22 remaining patients. The follow-up period ranges from 10 to 28 months (average follow-up longer than 17 months). Catheter ablation is a technique which is currently under evaluation. The very encouraging results obtained in this series suggest that it may replace surgery in the treatment of chronic refractory VT.

Adolescent↗