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Biomedical subjects

L Fauchier

Publications and source records attributed to L Fauchier.

At least 19 recordsLinked to original sources
PubMed2006

[Risk stratification in atrial and ventricular arrhythmias].

Atrial fibrillation, the most frequent arrhythmia, has a growing incidence with increasing age and the most important complication of the disease is thromboembolic events that may be prevented by antivitamin K. They are the most efficient therapeutic class for the prevention of these events but they are associated with an increased haemorrhagic risk leading to a reduced prescription in general practice. Optimisation of the management should be based on an individual evaluation of the thromboembolic and haemorrhagic risks, taking into account age, the presence of an associated heart disease, hypertension, diabetes, history of cerebrovascular event, history of previous haemorrhagic event and the ability to achieve a stable target INR. The challenge in ventricular arrhythmias lies in identifying a high risk of sudden death, mainly related to ventricular fibrillation. In patients with structural heart disease, left ventricular dysfunction is the strongest predictor of sudden death. Non invasive markers such as non sustained ventricular tachycardia, late ventricular potentials, decreased heart rate variability and baroreflex sensitivity, and repolarization altemans are further elements to assess risk. However, most of these markers have a poor positive predictive value and a low specificity. In patients with normal hearts, genetic predisposition may in the future identify high risk patients. The electrophysiologic study with programmed ventricular stimulation remains a costly and invasive method and only has a strong positive predictive value in ischemic cardiomyopathy. More precise algorithms for risk stratification are thus needed that may help the strategy of therapy with prophylactic implantable cardioverter defibrillator in the future.

4-Hydroxycoumarins↗
PubMed2006

Heart rate variability in rats with chronic hypoxic pulmonary hypertension.

The precise role of pulmonary hypertension as a possible factor inducing a decrease in heart rate variability is poorly known. Spectral analysis of heart rate variability (HRV) was carried out in 21 Wistar rats before and after exposure to normoxia (N = 10) or to 3 weeks of hypobaric hypoxia inducing chronic pulmonary hypertension and right ventricular hypertrophy (N= 11). Continuous ECG was recorded in conscious animal at rest. Compared to the control group, rats exposed to hypoxia had a similar heart rate but a lower overall HRV (total power, 27.9 +/- 15.2 vs. 57.6 +/- 24.7 ms2, P < 0.01). Low frequency power (0.25-0.8 Hz) and high frequency power (0.8-3 Hz) were similar in both groups suggesting that HRV was decreased in the very low frequency power (0-0.25 Hz). The effects of atropine and propranolol on heart rate and HRV were similar in rats exposed or not to hypoxia. HRV is decreased in rats with hypoxic induced pulmonary hypertension, mainly in the very low frequency band, suggesting an increase in sympathetic activity. However, this decrease is moderate and the modulation of HRV with pharmacologic autonomic blockade remains similar to that of normal rats.

Animals↗
PubMed2006

[Effects of delay in onset of revascularisation strategies in the acute phase of myocardial infarction].

BACKGROUND: thrombolysis (THL) and primary percutaneous coronary intervention (PCI) are therapeutic options in acute myocardial infarction (MI). These strategies have similar efficiency, particularly in the early phase. However, in these randomized studies, different times to treatment (TT) threshold are recognized as discriminant. OBJECTIVES: to validate, on a one year mortality criteria the best TT threshold in the real life. METHODS: 794 patients, admitted directly in our institution with a Ml< or =12 hours; 299 were treated by THL and 495 by PCI. The primary end-point was 1-year mortality according to TT and strategy of revascularization. Three TT thresholds were tested (120, 150 and 180 min) to define the best strategy of revascularisation. RESULTS: only the 150 min TT threshold showed a significant difference between the two strategies. If TT was less than 150 min, relative risk of 1-year mortality was 1.36 (p=0.62) for patients treated by THL compared to those treated with PCI. By contrast, the relative risk of one year mortality was 1.95 if Tr was greater than 150 min (p=0.02). CONCLUSION: TT is a key factor to define the best strategy of reperfusion. The critical threshold seems to be at 150 min. THL should be considered as a therapeutic choice only if administered within the first 150 min. After this delay, primary PCI should be preferred.

Angioplasty, Balloon, Coronary↗
PubMed2005

[Indications for automatic implantable defibrillators in patients with the Brugada syndrome].

Brugada syndrome is a primary electrical cardiac disease characterized by an ST segment elevation in V1-V2 leads on surface ECG and an increased risk of polymorphic ventricular tachyarrhythmia (ventricular tachycardia and/or ventricular fibrillation). The objective of the treatment is to prevent sudden death and it therefore includes in some cases the implantation of an automatic implantable cardiac defibrillator (AICD). In secondary prevention (i.e. after a first episode of resuscitated ventricular fibrillation), the implantation of AICD is mandatory (indication of class 1 level A). In primary prevention (i.e. in patients without documented ventricular fibrillation), the guidelines are not definitively established. We may consider two different clinical situations. First, the patient complains from syncope and this justifies the implantation of an AICD. Second, the patient is asymptomatic and the physician has to discuss the implantation of an AICD. Two parameters should be analysed: the pattern of ECG and the result of right programmed ventricular stimulation. An evident ST segment elevation (>2 mm) is associated with a high risk of sudden death. Likewise, the inducibility of a ventricular tachycardia or fibrillation is considered at the present time as a factor linked to sudden death and justifies the implantation of an AICD. On the other hand, a normal resting ECG only associated with a provoked ST segment elevation by class I antiarrhythmic drug (flecainide) defines a group of patients with a low risk of sudden death, and these patients do not require the implantation of an AICD.

Death, Sudden, Cardiac↗
PubMed2005

[Postmarketing surveillance in patients with cardiac pace-makers or automatic implantable defibrillators].

This article includes an overview of the actual French control and regulation system of the safety alerts involving pacemakers and implantable cardioverter-defibrillator and an evaluation of the general information and trends about the characteristics of the reported incidents obtained in the last years in that field. The national security agencies have the mission to collect the data on safety and efficacy of medical devices but manufacturers, physicians and patients also have a role to play. The technical appreciation of the necessity of a notification is not easy in some cases but the lack of notification of a severe incident may lead to heavy penal consequences. If doubtful cases, one should keep in mind the spirit of these safety systems: a collective insurance against the risks related to the use of medical devices. In the 10 last years, the annual advisory rate was increased. The pacemakers were recalled more frequently than implantable cardioverter-defibrillators in absolute value but less frequently in relative value (advisories per 100 person-years). This increase may be related to the growing number of device implants and expanding indications for device therapy, to the increasing sophistication of the devices and to the modifications in the regulation aspects of these problems with a closer attention of users and physicians to the several types of malfunctions.

Consumer Product Safety↗
PubMed2005

[Evaluation after 20 years of a case of Takayasu's disease that presented with aortic regurgitation].

Takayasu's disease is a segmental multifocal affection of medium and large arteries. The diagnosis is based on the association of stenotic and aneurismal lesions of the aorta and its branches secondary to an inflammatory infiltration of the media and adventitia. Cases of aortic regurgitation associated with aneurismal dilatation of the ascending aorta as the presenting features of Takayasu's disease, as in this case, are rare. Histological examination of the aortic wall may help establish the diagnosis by showing signs of aortitis. The other usual arterial lesions are sometimes missing at the initial phase of the disease. A late histological diagnosis may be difficult as the inflammatory lesions tend to be progressively replaced by fibrotic lesions or a banal atheroma.

Aortic Valve↗
PubMed2004

[Conduction defects and arrhythmias in peripheral myopathies].

The association between peripheral myopathies and cardiac complications is well established. However, until recently, the clinical and genetic variability of these pathologies limited our ability to recognise individual risk of complications, particularly in the more rare pathologies. Advances have been made in the understanding of the progression, in the physiopathology of molecular deficits and cardiac complications of the different types of muscular dystrophy. This has partially helped to identify the risk of cardiac complications. The commonest condition, Steinert's disease, is associated with a high incidence of atrioventricular block and atrial arrhythmias. Prophylactic implantation of a dual chamber pacemaker with diagnostic functions may be envisaged when the HV interval is greater than 70 ms, on endocavitary electrophysiological investigations. In other patients, follow-up by standard ECG and/or amplified averaged ECG and Holter monitoring is essential. The natural history of Duchenne and Becker muscular dystrophies and the Emery Dreifuss dystrophy have been better described in the last few years. Recommendations have been proposed for the cardiological follow-up of these patients. Empiric recommendations of the same type have been proposed for patients with shoulder and girdle myopathies and propositions for their management have also been made, the pertinence of which is still being evaluated. Our understanding of the incidence, the type, the physiopathology and molecular biology of the various peripheral myopathies and their cardiac complications has advanced considerably in recent years. This has led to the elaboration of new recommendations for diagnostic and therapeutic strategies in these patients.

Arrhythmias, Cardiac↗
PubMed2003

Comparative study of atrial vulnerability in patients with unexplained ischemic stroke or lone atrial paroxysmal fibrillation.

Strokes have a high prevalence, with a high rate of recurrence, and about 30-40% remain of unknown cause. Some patients might have asymptomatic paroxysmal atrial fibrillation (AF) which remains the main cause of embolic events. A latent atrial arrhythmogenic substrate may induce recurrent arrhythmias, including functional abnormalities such as nonuniform refractoriness and/or anatomic abnormalities such as atrial septum aneurysm (ASA) and patent foramen ovale (PFO). In 175 patients divided into three groups (Group I: 103 patients with unexplained ischemic stroke, Group II: 48 patients with paroxysmal AF and Group III or control group: 24 patients explored for another cause), such an atrial arrhythmogenic substrate was assessed by electrophysiological study. Groups I and II had a similar high rate of inducible atrial arrhythmias compared to control group III where no arrhythmia was induced. An induced atrial arrhythmia was observed in more than 50% of patients of Group I and in more than 70% of patients of Group II without any significant difference according to age. However, in 26 young patients of Group I who had a transesophageal echocardiography, both a high rate (46%) of ASA and/or PFO and a frequent latent atrial vulnerability (LAV) were observed, compared to older patients where an atrial septum abnormality was observed in only 21% of cases. Thus, among patients with stroke of unknown cause, a high percentage of them might have asymptomatic atrial paroxysmal arrhythmia. The predictive value of the electrophysiological study for spontaneous arrhythmias and recurrence of stroke remains to be demonstrated.

Atrial Fibrillation↗
PubMed2003

[Conduction defects as the presenting feature of sarcoidosis or observed during the course of the disease: regression with corticoid steroid therapy].

Cardiac sarcoidosis is often unrecognised because of the absence of specific clinical and electrical signs. The consequences are serious, the main risk being sudden death due to conduction defects (24 to 31% of cases) or ventricular arrhythmias. Any conduction defect without an obvious cause in a young patient should suggest a possible diagnosis of sarcoidosis. The confirmation is histological when giant cell non-caseuting epithelioid granuloma is demonstrated but myocardial biopsies are only positive in 20% of cases. Therefore, biopsy of accessible organs such as salivary glands is recommended. Diagnostic strategy consists in searching for signs of systemic sarcoidosis, and, when the diagnosis has been established, perform a complete work-up with echocardiography, dipyridamole myocardial scintigraphy, cardiac MRI and 24 hour ambulatory ECG recordings (Holter). The only proven treatment is steroid therapy with occasional spectacular observations of reversibility of arrhythmias or conduction defects.

Adrenal Cortex Hormones↗
PubMed2003

[Arrhythmias of primary hypertrophic cardiomyopathy].

Primary hypertrophic cardiomyopathy is a genetic disease causing sarcomere dysfunction. The structural and functional myocardial changes combine to produce cardiac arrhythmias related to reentry phenomena and to triggered automatic activity. The commonest arrhythmias are atrial fibrillation and ventricular arrhythmias; junctional tachycardias via the bundle of Kent are rare. Atrial fibrillation and the Wolff-Parkinson-White syndrome are more commonly associated with certain genetic mutations. Their treatment is mainly based on medication with amiodarone or on radiofrequency ablation in cases of junctional tachycardia. Ventricular arrhythmias are mainly isolated ventricular extrasystoles and non-sustained ventricular tachycardia. The prognostic significance of the latter has been subject of debate for many years but recent studies report a poor prognosis with non-sustained ventricular tachycardia especially in the young patients. Sustained ventricular tachycardia and ventricular fibrillation, though life-threatening complications of hypertrophic cardiomyopathy, are rarely documented and justify implantation of an automatic defibrillator as the risk of recurrence is high. The main objective of the cardiologist in cases of primary hypertrophic cardiomyopathy is to identify the patient at high risk of sudden death. This requires analysis of several parameters: clinical, anatomical, haemodynamic, rhythmic, functional and genetic. The presence of at least two risk factors for sudden death justifies preventive measures. The implantation of an automatic defibrillator is the most reliable form of treatment.

Arrhythmias, Cardiac↗
PubMed2002

Physical training increases heart rate variability in healthy prepubertal children.

BACKGROUND: The aim of the present study was to evaluate the effect of an endurance training program on heart rate variability (HRV) in prepubertal healthy children and to determine the relationships between HRV components and training-induced cardiac adaptations. METHODS: Nineteen prepubertal children (aged 10-11 years old) took part in this study: 12 children were assigned to participate in a 13-week endurance training program (3 x 1 h week-1; intensity, > 80% HRmax) and 7 children served as a control group. Before and after the 13-week study period, all the children were tested for maximal oxygen uptake (V O(2max)), HRV was measured by spectral and time domain analysis of 5 h night ECG recordings, and left ventricular (LV) cardiac morphology and function were assessed by means of Doppler-Echocardiography. RESULTS: V O(2max) increased significantly (+15.5% +/- 12.1; P < 0.01) after the training program. All the frequency domain components (absolute values) increased after training except the low (LF) to high (HF) frequency ratio. Also, LF and HF did not change when expressed relative to total power. For the time domain components, only N-N intervals, the standard deviation of all N-N and the average of all 5 min standard deviations of N-N increased after training. Our training program induced also an increase in LV internal diameter and mass as well as an enhancement in early diastolic passive LV filling with a concomitant reduction in late diastolic active LV filling. These cardiac morphological and functional adaptations did not correlate however, with the autonomous nervous system modifications due to training. CONCLUSION: Our study shows that an endurance training program had a positive effect on aerobic potential, morphological and functional cardiac parameters and on nocturnal global HRV in healthy prepubertal children without inducing sympathetic and parasympathetic modifications.

Case-Control Studies↗
PubMed2000

Association between heart rate-corrected QT interval and coronary risk factors in 2,894 healthy subjects (the DESIR Study). Data from an Epidemiological Study on the Insulin Resistance syndrome.

In the prospective Data from an Epidemiological Study on the Insulin Resistance Syndrome, 2,894 healthy subjects aged 30 to 64 years had determinations of fasting glucose, insulin, serum lipid and fibrinogen concentrations, blood pressures, body mass index, and waist-hip ratio, as well as tobacco and alcohol consumptions and physical activity. A 12-lead electrocardiogram with automatic measurement of the QT interval was recorded and the formula used for heart rate correction was based on the best-fit regression between QT and heart rate. The QT duration was influenced by glucose homeostasis in both sexes, and increased in men with physical activity; there was a dose-effect relation for men who smoked.

Adult↗
PubMed2000

Long-term prognostic value of time domain analysis of signal-averaged electrocardiography in idiopathic dilated cardiomyopathy.

The aim of this study was to evaluate the long-term prognostic value of signal-averaged electrocardiography (SAECG) in idiopathic dilated cardiomyopathy (IDC). Time domain analysis of SAECG was assessed in 131 patients with angiographically confirmed IDC (age 52+/-12 years; 108 men; left ventricular ejection fraction 33+/-12%) using specific criteria in 44 patients with bundle branch block. Late potentials (LP) on SAECG were present in 27% of the patients. Patients with LP had a similar left ventricular ejection fraction and a similar left ventricular end-diastolic diameter than patients with a normal SAECG. With a follow-up of 54+/-41 months, 24 patients suffered cardiac death and 19 had major arrhythmic events (sudden death, resuscitated ventricular fibrillation, or sustained ventricular tachycardia). Patients with LP had an increased risk of all-cause cardiac death (RR 3.3, 95% confidence interval 1.5 to 7.5, p = 0.004) and of arrhythmic events (RR 7.2, 95% confidence interval 2.6 to 19.4, p = 0.0001). Using multivariate analysis, only LP on SAECG (p = 0.001), reduced SD of all normal-to-normal intervals (SDNN) (p = 0.002), increased pulmonary capillary wedge pressure (p = 0.005), and history of sustained ventricular tachyarrhythmia (p = 0.02) predicted cardiac death. A history of previous sustained ventricular tachyarrhythmia (p = 0.0001), reduced SDNN (p = 0.003), and LP on SAECG (p = 0.006) were the only independent predictors of major arrhythmic events. Results were not altered when considering separately patients with or without bundle branch block, or after exclusion of patients with a history of sustained ventricular tachyarrhythmia. This study is one of the first to suggest that LP on SAECG is an independent predictor of all-cause cardiac death and is of high interest for arrhythmia risk stratification in IDC.

Arrhythmias, Cardiac↗