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Samuel Lévy

Publications and source records attributed to Samuel Lévy.

14 recordsLinked to original sources
PubMed2006

Drug Insight: angiotensin-converting-enzyme inhibitors and atrial fibrillation--indications and contraindications.

Large clinical trials have demonstrated that angiotensin-converting-enzyme (ACE) inhibitors are associated with beneficial outcomes in patients with arterial hypertension, heart failure, coronary artery disease, or a combination of these conditions. Other reports have suggested that ACE inhibitors prevent the development or recurrence of atrial fibrillation (AF), a common arrhythmia. In the TRACE trial, in patients with reduced left ventricular function after myocardial infarction, trandolapril reduced the frequency of AF. In the SOLVD trial, a 78% reduction in the frequency of AF after infarction was noted with enalapril compared with placebo. Studies in patients with persistent AF undergoing cardioversion suggest that ACE inhibitors improve outcomes and prevent AF recurrences. The mechanism of AF prevention by ACE inhibitors is unclear, but experimental data show prevention or attenuation of pacing-induced atrial remodeling with ACE inhibitor use. ACE inhibitors decrease angiotensin II concentration; angiotension II stimulates mitogen-activated protein kinases, which in turn activate fibrosis formation and lead to conduction heterogeneity and induction of AF. On the other hand, AF induces atrial dilatation, atrial stretch and atrial secretion of ACE. Among other properties, ACE inhibitors have a sympatholytic effect and increase baroreceptor sensitivity. This review discusses the current data on the use of ACE inhibitors for AF prevention. Although these drugs represent a promising therapeutic option for AF patients, the data so far seem only supportive rather than definitive. Prospective trials are required to validate the benefit of ACE inhibitors and to investigate which patients are most likely to benefit from this pharmacological therapy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2005

Atrial fibrillation management: a prospective survey in ESC member countries: the Euro Heart Survey on Atrial Fibrillation.

AIMS: To describe atrial fibrillation (AF) management in member countries of the European Society of Cardiology (ESC) and to verify cardiology practices against guidelines. METHODS AND RESULTS: Among 182 hospitals in 35 countries, 5333 ambulant and hospitalized AF patients were enrolled, in 2003 and 2004. AF was primary or secondary diagnosis, and was confirmed on ECG in the preceding 12 months. Clinical type of AF was reported to be first detected in 978, paroxysmal in 1517, persistent in 1167, and permanent in 1547 patients. Concomitant diseases were present in 90% of all patients, causing risk factors for stroke to be also highly prevalent (86%). As many as 69% of patients were symptomatic at the time of the survey; among asymptomatic patients, 54% were previously experienced symptoms. Oral anticoagulation was prescribed in 67 and 49% of eligible and ineligible patients, respectively. A rhythm control strategy was applied in 67% of currently symptomatic patients and in 44% of patients who never experienced symptoms. CONCLUSION: This survey provides a unique snapshot of current AF management in ESC member countries. Discordance between guidelines and practice was found regarding several issues on stroke prevention and antiarrhythmic therapy.

Adult↗
PubMed2005

Internal defibrillation: where we have been and where we should be going?

Internal cardioversion has been developed as an alternative technique for patients who are resistant to external DC cardioversion of atrial fibrillation (AF) and was found to be associated with higher success rates. It used initially high energies (200-300 J) delivered between an intracardiac catheter and a backplate. Subsequent studies have shown that it is possible to terminate with energies of 1 to 6 Joules, paroxysmal or induced AF in 90 percent of patients and persistent AF in 75 percent of patients, using biphasic shocks delivered between a right atrium-coronary sinus vectors. Consequently, internal atrial defibrillation can be performed under sedation only without the need for general anesthesia. Recently developed external defibrillators, capable of delivering biphasic shocks, have increased the success rates of external cardioversion and reduced the need for internal cardioversion. However, internal defibrillation is still useful in overweight or obese patients, in patients with chronic obstructive pulmonary disease or asthma who are more difficult to defibrillate, and in patients with implanted devices which may be injured by high energy shocks. Low energy internal defibrillation has also proven to be safe and this has prompted the development of implantable devices for terminating AF. The first device used was the Metrix system, a stand-alone atrial defibrillator (without ventricular defibrillation) which was found to be safe and effective in selected groups of patients. Unfortunately, this device is no longer being marketed. Only double chamber defibrillators with pacing capabilities are presently available: the Medtronic GEM III AT, an updated version of the Jewel AF and the Guidant PRIZM AVT. These devices can be patient-activated or programmed to deliver automatically ounce atrial tachyarrhythmias are detected, therapies including pacing or/and shocks. Attempts to define the group of patients who might benefit from these devices are described but the respective role of atrial defibrillators versus other non-pharmacologic therapies for AF, such as surgery and radiofrequency catheter ablation, remains to be determined. Advantages and limitations or atrial defibrillators and approaches to reduce shock related discomfort which may be a concern in some patients, are reviewed. Studies have shown that despite shock discomfort, quality of life was improved in patients with atrial defibrillators and the need for repeated hospitalizations was reduced. The cost of these devices remains a concern for the treatment of a non-lethal arrhythmia. Attention that atrial defibrillators will receive from cardiologists and from the industry in the future, will depend of the long-term results of other non-pharmacological options and of the identification of the group of AF patients which will require restoration and maintenance of sinus rhythm. But there is no doubt that selected subsets of patients with AF could benefit from atrial defibrillation.

Atrial Fibrillation↗
PubMed2004

[Atrial fibrillation].

Atrial fibrillation is a common arrhythmia which consequences include disabling symptoms, haemodynamic impairment and frightening embolic complications. In 3/4 cases, they are represented by cerebrovascular accidents responsible of death or disabling sequella. Underlying heart disease is present in 70% of AF patients. Endpoints of therapy include: 1. prevention of embolic complications using oral anticoagulation in patients at risk; 2. control of symptoms and prevention of haemodynamic impairment either by restoring and maintaining sinus rhythm or by controlling ventricular heart rate. The same principles should be applied for emergency treatment: aside from AF with haemodynamic compromise (hypotension or syncope) which requires urgent electrical cardioversion, AF termination may be obtained with intravenous or oral antiarrhythmic therapy or the treatment confined to slowing of heart rate. Selecting the appropriate antiarrhythmic therapy for prevention of recurrences is based on the type of AF, paroxysmal or persistent, symptoms, underlying heart disease and left ventricular function. For patients refractory to drug therapy, non pharmacologic treatment represents an option including pacemaker, double chamber defibrillator, and radiofrequency ablation of ectopic foci most often located in the pulmonary veins or pulmonary vein isolation or surgery particularly if there is an indication for open-chest surgery. Non-pharmacological therapies should be restricted to very symptomatic patients who failed pharmacological therapy.

Atrial Fibrillation↗
PubMed2003

Intra-atrial thrombosis and pulmonary embolism complicating pacemaker leads for cardiac resynchronization therapy.

This is the first report of intracardiac thrombi and pulmonary embolism complicating pacemaker leads implanted for cardiac resynchronization therapy. Prompt diagnosis and successful therapy with a thrombolytic agent lead to a favourable outcome. This report suggests that long-term oral anticoagulation should be considered in patients with depressed left ventricular function undergoing cardiac resynchronization therapy in order to prevent this potentially serious complication.

Aged↗
PubMed2002

Role of endogenous adenosine as a modulator of syncope induced during tilt testing.

BACKGROUND: Previous reports that used head-up tilt testing and adenosine administration have suggested that adenosine may be an important endogenous mediator that may trigger a vasovagal response in susceptible patients. However, little is known regarding endogenous adenosine plasma levels (APLs) during vasovagal syncope provoked by tilt testing. The aim of this study was to determine whether APLs differ in patients with a positive head-up tilt test compared with those with a negative test and whether APLs are modified during tilt-induced vasovagal syncope. METHODS AND RESULTS: APLs (mean+/-SEM) were measured during head-up tilt test in 26 patients who presented with unexplained syncope. In the 15 patients with a negative test, APLs were 0.39+/-0.03 micromol/L at baseline, 0.22+/-0.03 micromol/L immediately after tilting, and 0.44+/-0.03 micromol/L after 45 minutes. APLs were significantly higher in the 11 patients with a positive test (2.66+/-0.67 micromol/L at baseline and 3.22+/-0.85 micromol/L immediately after tilting) than in those with a negative test. During tilt testing-induced syncope, APLs increased to reach 4.03+/-0.66 micromol/L (ie, a 52% increase compared with baseline levels; P<0.02). Furthermore, we observed that the higher the APL during syncope, the shorter the time to appearance of symptoms. CONCLUSIONS: This study showed that APLs were higher in patients with a positive tilt test than in patients with a negative test and that they increased during tilt testing-induced syncope. These observations suggest that adenosine release may be involved in the triggering mechanism of syncope induced during tilt testing.

Adenosine↗
PubMedDate not supplied

Remodeling of Na,K-ATPase, and membrane fluidity after atrial fibrillation in sheep.

UNLABELLED: Atrial fibrillation (AF) is accompanied by various changes in ion channels that cause atrial electrophysiological remodeling. The enzyme Na,K-ATPase is also a major cellular mechanism for the regulation of ion homeostasis. During AF, Na,K-ATPase may be regulated by synthesis of its alpha- and beta-subunits as well as changes in membrane fluidity. To test this hypothesis, we studied the effect of pacing-induced AF in sheep on atrial Na,K-ATPase alpha- and beta-subunits and on membrane fluidity as well. METHODS: A group of six sheep (AF group) was subjected to overdrive electrical stimulation of the right atrium in order to induce AF. A group of six sham operated sheep served as control. All paced sheep developed multiple episodes of sustained AF with a mean total duration of 110 min over a 2-hours period. Protein expression of Na,K-ATPase alpha- and beta-subunits in atrial microsomal membranes was assayed by Western blotting analysis. When significant changes in membrane expression were observed, transcriptional regulation was analysed by Northern blotting. Membrane fluidity was assessed on atrial microsomal fractions by anisotropy measurements using the fluorescent probe diphenylhexatriene. RESULTS: Atrial fibrillation enhanced the expression of the Na,K-ATPase beta1-subunit at both membrane and mRNA levels. Anisotropy values were higher in AF group than in control group, indicating a decreased fluidity of the membranes isolated from paced sheep atria. CONCLUSION: These data are the first evidence for an enhanced Na,K-ATPase beta1-subunit expression in membrane during AF. Membrane rigification represents a new factor of tachycardia-induced atrial remodeling.

Animals↗
PubMedDate not supplied

[Heart rate, a major prognostic factor of cardiovascular risk].

The prognostic value of heart rate (HR) was analysed based on the reports from the literature in the general population and in patients with coronary artery disease (CAD). Multivariate analyses showed that elevated resting HR was found to be an independent predictor of total and cardiovascular mortality. The behaviour of HR during exercise testing was predictive of sudden death. The beneficial effects of betablockers in post-infarction patients are well established. Calcium channel blockers that increase resting HR are associated with a deleterious effect on mortality. Therefore, resting HR should not be overlooked in risk stratification of CAD patients. Reduction of resting HR should be viewed as an attractive therapeutic target in CAD patients.

Adrenergic beta-Antagonists↗