PubMed Health⌕ Search

Biomedical subjects

S Lévy

Publications and source records attributed to S Lévy.

At least 19 recordsLinked to original sources
PubMed1992

Direct current cardioversion of established atrial fibrillation.

Restoration and maintenance of sinus rhythm is a desirable end point in patients with chronic atrial fibrillation. If clinically indicated, external cardioversion using direct current is the method of choice in most centers. The results range from 20 to 90% and are highly influenced by the underlying etiology. A number of determinants including age, duration of atrial fibrillation, and size of left atrium are usually taken into account in the indications but have been recently questioned. The use of prophylactic antiarrhythmic therapy has been shown to reduce the recurrence of atrial fibrillation significantly, but concerns remain regarding the safety of this treatment. In patients who failed external cardioversion, shocks delivered within the right atrium according to a recently described technique may be attempted. The initial results are promising, as 83% of patients are successfully cardioverted and 46% of patients are in sinus rhythm at 12 months. This new technique offers an additional alternative in patients with chronic atrial fibrillation and may therefore reduce the incidence of frightening embolic complications.

Adult↗
PubMed1992

A randomized comparison of external and internal cardioversion of chronic atrial fibrillation.

BACKGROUND: Delivery of shocks within the right atrium has been reported to be more effective than conventional external shocks in converting atrial fibrillation (AF), but these two cardioversion techniques have never been compared prospectively. The purpose of this study was to compare the efficacies of external and internal cardioversion in patients with chronic AF unresponsive to prior attempts at electrical and/or pharmacological cardioversion. Low-dose amiodarone was used in all patients after cardioversion to suppress recurrences of AF. METHODS AND RESULTS: One hundred twelve patients with AF of at least 1 month in duration were randomly assigned to undergo external cardioversion with 300-360-J shocks or internal cardioversion with 200-300-J shocks delivered through a standard electrode catheter within the right atrium. The patients were treated with amiodarone (200 mg/day 5-7 days/week) for 1 month before electrical cardioversion and afterward if the cardioversion was successful. The patients were evaluated at regular intervals during 1 year of follow-up. The efficacy of internal cardioversion was significantly greater than that of external cardioversion (91% versus 67%, p = 0.002). The only variable that was associated with the outcome of cardioversion was body weight. Among patients in whom sinus rhythm was restored, AF recurred as often after internal and external cardioversion; at 1 year of follow-up, 37% of patients in whom external or internal cardioversion had been effective were still in sinus rhythm. Patients who had undergone an attempt at electrical cardioversion before entry into this study were less likely to remain in sinus rhythm after cardioversion. The only complications of cardioversion were one instance of cerebral thromboembolism after external cardioversion and one instance of transient pulmonary edema after internal cardioversion. Therapy with amiodarone was discontinued because of an adverse drug effect in only three patients. CONCLUSIONS: Internal cardioversion is more effective than external cardioversion in restoring sinus rhythm and is as safe as external cardioversion in patients with chronic AF. The recurrence rate of AF is the same after both types of cardioversion. If conventional electrical cardioversion is ineffective, internal cardioversion should be attempted. The combination of low-dose amiodarone and external or internal cardioversion may result in maintaining sinus rhythm long-term in patients with refractory AF.

Amiodarone↗
PubMed1992

[Comparative effects of anti-arrhythmia agents on ventricular refractory period and prevention of ventricular tachycardia induced by stimulation].

The efficacy of antiarrhythmic drugs is attributed to their actions on the refractory periods or conduction velocity in the reentry circuit. The aim of this study was to determine the relationship between these factors and the prevention of electrically inducible ventricular tachycardia (VT). Twenty-seven patients with sustained monomorphic postinfarction VT underwent programmed stimulation under basal conditions and after administration of oral Class I antiarrhythmic drugs. The protocol of stimulation consisted of delivering one to three extrastimuli to the right ventricular apex on two basic cycle lengths. Sustained VT was induced in all patients. After the same protocol under antiarrhythmic therapy (1 to 5 tests, average 2.9 +/- 1) sustained VT could not be induced in 12 patients (44%). The effective right ventricular refractory period was significantly increased in patients without inducible VT under treatment (247 +/- 18 versus 302 +/- 26 ms). The increase in the right ventricular effective refractory period in patients with persistence of inducible VT was much less (from 270 +/- 28 to 287 +/- 30 ms). In all patients in whom several antiarrhythmic drugs were tested the right ventricular effective refractory period was higher when the treatment was judged to be effective (299 +/- 27 ms) than ineffective (272 +/- 27, p < 0.02). The prevention of inducible VT by class I antiarrhythmic agents seems therefore to be related to their effect on the ventricular refractory period.

Anti-Arrhythmia Agents↗
PubMed1992

[Parkinson syndrome, a possible adverse effect of calcium inhibitors].

The effects of calcium inhibitors are not limited to the muscles and may affect other systems and cause varied side effects. Two cases of Parkinsonian syndrome occurring after starting therapy with calcium inhibitors (verapamil in one case and diltiazem in the other) are reported. Complete regression of the symptoms after withdrawing the drugs was strongly in favour of a causal relationship. The condition could be due to inhibition of the calcium channels in the central nervous system disturbing neurotransmission. This seems to be a rare side effect as there have only been three other reported cases of secondary extrapyramidal syndromes in the literature. However, a Parkinsonian syndrome is very invalidating and clinicians using this family of drugs should be aware of this possible complication.

Aged↗
PubMed1992

[Atrioventricular block at nodal and infrahissian level during atrial tachycardia. Apropos of a case].

The authors report the case of a patient with atrial tachycardia and surface electrocardiographic signs of left anterior hemiblock and complete right bundle branch block with 10/3 atrioventricular block. The regularity of the RR intervals which were an exact multiple of the atrial cycle suggested the absence of a Wenckebach phenomenon. The sequence of atrioventricular conduction cannot be explained by classical models of intranodal conduction. Endocavitary recordings confirmed this hypothesis. They showed block at 2 levels: supra- and infrahisian. The suprahisian block functioned in the 2/1 mode and the infrahisian block in the 5/3 mode without incremental conduction distal to the His potential before the apparition of block. A double zone of intrahisian block could explain the observed sequence of atrioventricular conduction. The absence of Wenckebach phenomenon on the surface ECG during tachycardia could be a sign of infrahisian block. The authors suggest that the association of this sequence of atrioventricular conduction with intraventricular conduction defects is a formal indication for electrophysiological studies.

Aged↗
PubMed1991

Diagnostic approach to cardiac arrhythmias.

The diagnostic approach to cardiac arrhythmias should be logical and starts with the clinical history, which provides two types of information: (a) the presence of symptoms, and (b) the clinical context, including the presence of an underlying heart disease. Clinical history and examination are helpful in the choice of pertinent invasive or noninvasive tests. The tolerance of the arrhythmia is not helpful in determining the type of arrhythmia because ventricular tachycardia, for example, may be well tolerated or even asymptomatic. The electrocardiogram (ECG) in sinus rhythm may be suggestive of the origin or etiology of arrhythmia as the presence, for example, of the Wolff-Parkinson-White pattern. An essential step in the diagnostic approach to arrhythmia is the ECG documentation. Ambulatory Holter monitoring, radiotelemetry, intermittent recorders, exercise testing, and electrophysiological testing will help in this endeavor. The latter is particularly useful in paroxysmal circus movement tachycardias. Once the tachycardia is recorded, a number of clues, including the regularity of the RR interval and the width of the QRS complex, may facilitate the diagnosis. In tachycardias with wide QRS complexes, preexcitation has to be excluded. The first step is then to look for atrioventricular dissociation, which is diagnostic of ventricular tachycardia. Other diagnostic clues (QRS duration, axis deviation, QRS morphology) may be useful. In case of difficulty because of preexisting bundle branch block or aberrancy, esophageal, right atrial, or His bundle recordings are indicated. If the tachycardia is not well tolerated, prompt termination with electrical DC shock should be performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Value of systematic preventive antibiotherapy in cardiac pacemaker implantation].

The aim of this study was to assess the usefulness of prophylactic antibiotics during insertion of a cardiac pacemaker, in order to avoid infection of exteriorisation of infectious origin. The study involved two groups. One hundred and eight patients made up group I, a control group without the use of prophylactic antibiotics. Group II consisted of 101 patients who were given an intravenous injection of 1 or 2 g of oxacillin before surgery, followed up by four days of oral oxacillin (3 g per day). Serum oxacillin levels at the end of the procedure were 0.37 +/- 0.09 mcg/ml, falling within the range of minimum inhibitory concentrations of methicillin-sensitive staphylococci. In the patients of the control group, followed up for 1 to 36 months (mean 12 +/- 11 months), during the first 2 months there were 2 infections, 4 exteriorisations and one cutaneous erosion over the pacemaker. In addition, one exteriorisation and one infection occurred at 17 and 29 months respectively. In patients with exteriorisation of their pacemaker device, there was nothing to suggest an infection and bacteriological specimens were sterile. No obvious infections nor any cutaneous complications occurred in the patients of group II, with prophylactic antibiotics, followed up for 1 to 21 months (mean 6 +/- 5 months). In conclusion, anti-staphylococcal antibiotic treatment appears not only to be capable of avoiding cardiac pacemaker infections but also of preventing exteriorisation of the pacemaker device, which may be linked to hidden infections. A randomised study is nevertheless necessary to confirm this hypothesis.

Adult↗
PubMed1990

[Prevalence of alcoholic diseases. At a teaching hospital of the Paris suburbs].

During the last 15 days of January 1989, the 757 patients admitted for more than 48 hours in any of the departments of Hôpital Beaujon (Clichy) were investigated for diseases that were certainly or probably related to alcoholism, and in order to detect drinkers at high risk, the amount of alcohol consumed in a week was recorded. The prevalence of alcohol-related diseases was 14.7 per cent (range: 12.2 per cent-17.2 per cent) and that of alcohol consumers at high risk was 4.2 per cent (range: 2.8 per cent-5.6 per cent).

Adult↗
PubMed1990

Cyclic AMP synthesis in Escherichia coli strains bearing known deletions in the pts phosphotransferase operon.

A series of isogenic strains harboring known deletions in the pts operon of Escherichia coli have been constructed by reverse genetics. Strains bearing deletions for the whole pts operon failed to grow on maltose or on carbon sources of the same class. In these strains the total cAMP synthesis was significantly lower than in a strain deleted only for the crr gene. This indicated that enzyme I or phosphorylated histidine-containing phosphotransferase protein in addition to its role in phosphorylating enzyme IIIGlc, is involved in adenylate cyclase (AC) activation or cAMP excretion. It was further shown that deletions in the pts operon do not affect synthesis of AC.

Adenylyl Cyclases↗
PubMed1990

Secondary prevention after myocardial infarction: in favor of beta-blockers.

A large number of pharmacological trials have been carried out, attempting to reduce the mortality (10-15%) in the year following of an acute myocardial infarction (MI) and/or the recurrence of ischemic events. Thrombolytic therapy and beta-blockade are the only interventions to be associated with a significant decrease in cardiac mortality. Early intervention with intravenous beta-blockers aims at limiting infarct size and at decreasing mortality. The Swedish study using intravenous (15 mg) followed by oral (200 mg/day) metoprolol showed a 36% reduction in mortality after the first week, a benefit persisting after 1 year. The combination of streptokinase and intravenous atenolol is safe and may be beneficial in selected patients. Large-scale controlled multicenter studies have shown that beta-blockers introduced within the first 3 days after acute MI significantly reduce total mortality and/or sudden death in the year following the acute event. Some of these studies demonstrate a reduction in recurrence of MI. The reduction (averaging 25%) in mortality may be explained by the anti-ischemic action of beta-blockers and the prevention of arrhythmia-induced death. Introduced early, beta-blockers may reduce the size of the initial MI as well as subsequent infarction and/or ischemia. Furthermore the antistress action of beta-blockers results in a decrease in free fatty acids, with their untoward effect in acute MI. Antiplatelet aggregation may also play a role. These properties of beta-blocking agents should be utilized in every patient with acute MI in the absence of any major contraindication. Elective indications include patients with hypertension, angina pectoris, and/or ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1990

[Electrophysiologic evaluation and follow-up of patients with a syncopal episode of unknown origin].

The etiology of syncope of presumed cardiac origin can be determined by clinical and electrocardiographic examination with Holter monitoring in about 50 per cent of cases. The aim of this study was to review the data of electrophysiological investigation and the outcome of the patients in whom a cardiac pacemaker was eventually implanted, in those cases in whom the initial work-up had been negative. Ninety four patients, all of whom underwent standardised electrophysiological investigation, were included. The results of the investigations enabled us to identify three groups of patients: Group I: patients in whom the criteria did not suggest a cardiac origin of syncope; Group II: with criteria possibly suggesting a cardiac origin and Group III in which the criteria were strongly suggestive of a cardiac origin. A cardiac pacemaker was implanted systematically for AV block in Group III; on the other hand, this was very rare (only 1 patient) in Group I, and the indication in Group II depended on age and the history of recurrent syncope. Ninety patients (96%) were followed up for an average of 39.3 +/- 15.3 months. There was a very low incidence of recurrent syncope irrespective of the original classification, so confirming the value of electrophysiological investigations for cardiac pacemaker implantation in this type of patients. In addition, negative electrophysiological investigations allowed identification of a group of patients with a low mortality and low risk of recurrent syncope.

Aged↗
PubMed1989

Antisense expression at the ptsH-ptsI locus of Escherichia coli.

A Mud(Ap, lac) prophage has been shown to be inserted into the ptsH gene of E. coli. The insertion is likely to have generated an operon fusion revealing antisense transcription at this locus. This suggests that the ORF previously identified, overlapping with ptsH ORF in the opposite orientation, might be functional. A model of regulation for the ptsH-ptsI-crr operon transcription is presented which accounts for antisense transcription.

Cloning, Molecular↗
PubMed1989

Non-medical therapy of ventricular tachyarrhythmias.

In recent years, development of non-pharmacological therapy has provided new therapeutic possibilities for patients with ventricular tachyarrhythmias. One of the major advances is the automatic cardioverter-defibrillator which has reduced dramatically the number of arrhythmic deaths in patients with ventricular tachycardia or fibrillation. Surgery of ventricular arrhythmias represents an interesting alternative in selected patients as it provides a cure. Electrical ablation of the arrhythmogenic substrates is still experimental. The mortality associated with the procedure in patients with coronary artery disease represents a serious limitation. A careful selection of the indications in order to tailor therapy to the patient is needed and guidelines are proposed.

Coronary Disease↗