[Implantable cardioverter defibrillators in pediatric patients: results in a series of 33 cases]. / Le défibrillateur automatique implantable chez l'enfant et l'adolescent: indications, complications et résultats à propos d'une étude multicentrique française de 33 cas.

UNLABELLED: Implantable defibrillator is the recognized treatment of sudden cardiac death. Miniaturization of the devices allows implantation in children. METHODS: This multicentric retrospective study analyzed data of 33 children aged 18 years and less who were implanted from 1990 to 2005. RESULTS: Age of patients are 10 to 18 years, 20 patients were implanted after a resuscitation of sudden death, 10 after a syncope, 2 after a ventricular tachycardia and 1 in a prophylactic way. Tachycardias on primary electrical disease are most frequent (46%). Hypertrophic cardiomyopathy accounts for 22%, DAVD for 14%, congenital cardiopathies for 12%. Seventeen patients received appropriate shocks and 14 patients had inappropriate shocks. There were two unexplained deaths. Five leads fractures and two device infections were noted. CONCLUSION: Implantable defibrillator is an effective treatment for children high-risk of sudden death. Occurrence of inappropriate shocks due to sinusal tachycardia, infections and leads fractures are frequent.

[Clinical evolution of patients following investigation of atrial vulnerability after a first cerebral ischaemic accident]. / Evolution clinique des patients ayant eu une recherche de vulnérabilité atriale après un premier accident ischémique cérébral.

Atrial vulnerability reflects the ability of the atrium to fibrillate. ISAV (Ischemic stroke and atrial vulnerability) is a French epidemiological registry whose main goal is to assess the evolution modalities of patients in whom an electrophysiological study of the atrium has been performed. A group of 269 patients with a history of non elucidated ischemic stroke and an electrophysiological study of the atrium performed in a mean delay of 3 months after the stroke has been included. Their mean age at the time of the stroke was 55 +/- 15.8 years. The electrophysiological study has measured the effective refractory period of the atrium, the locoregional right intra-atrial conduction time, the index of latent atrial vulnerability and assessed the inductibility. The mean delay between the date of the stroke and the date of the last news was 4.4 +/- 2.8 years. We observed 12 deaths and 11 patients presented during the follow up a spontaneous atrial arrhythmia and 17 a recurrence of stroke. If we consider the occurrence of the 28 combined events (atrial arrhythmia and/or stroke), it is not correlated with the presence of an atrial septal defect nor with the existence of an atrial vulnerability. On the contrary this occurrence is correlated with tobacco consumption and/or arterial hypertension; 82% of patients have these risk factors versus 54% of patients without events (p = 0.004). This association is not significant in patients younger than 55 years.

Critical analysis of dual-chamber implantable cardioverter-defibrillator arrhythmia detection : results and technical considerations.

BACKGROUND: One of the perceived benefits of dual-chamber implantable cardioverter-defibrillators (ICDs) is the reduction in inappropriate therapy due to new detection algorithms. It was the purpose of the present investigation to propose methods to minimize bias during such comparisons and to report the arrhythmia detection clinical results of the PR Logic dual-chamber detection algorithm in the GEM DR ICD in the context of these methods. METHODS AND RESULTS: Between November 1997 and October 1998, 933 patients received the GEM DR ICD in this prospective multicenter study. A total of 4856 sustained arrhythmia episodes (n=311) with stored electrogram and marker channel were classified by the investigators; 3488 episodes (n=232) were ventricular tachycardia (VT)/ventricular fibrillation (VF), and 1368 episodes (n=149) were supraventricular tachycardia (SVT). The overall detection results were corrected for multiple episodes within a patient with the generalized estimating equations (GEE) method with an exchangeable correlation structure between episodes. The relative sensitivity for detection of sustained VT and/or VF was 100.0% (3488 of 3488, n=232; 95% CI 98.3% to 100%), the VT/VF positive predictivity was 88.4% uncorrected (3488 of 3945, n=278) and 78.1% corrected (95% CI 73.3% to 82.3%) with the GEE method, and the SVT positive predictivity was 100.0% (911 of 911, n=101; 95% CI 96% to 100%). CONCLUSIONS: A structured approach to analysis limits the bias inherent in the evaluation of tachycardia discrimination algorithms through the use of relative VT/VF sensitivity, VT/VF positive predictivity, and SVT positive predictivity along with corrections for multiple tachycardia episodes in a single patient.

Signal-averaged electrocardiography and detection of heart transplant rejection: comparison of time and frequency domain analyses.

To evaluate the role of the signal-averaged electrocardiogram (ECG) in the detection of heart transplant rejection, findings on 277 ECGs were compared with those in 218 endomyocardial biopsy specimens in 25 patients followed up for a median duration of 5.2 months (range 7 days to 17.5 months). Signal-averaged ECGs obtained at intervals of 16.4 +/- 22.3 days were analyzed in the time domain before and after high pass filtering at 25 and 70 Hz. Frequency domain analysis was performed with use of a fast Fourier transform algorithm. Sixteen severe rejection episodes requiring treatment were observed. These episodes induced significant decreases in peak and root-mean-square voltages of both filtered and unfiltered QRS complexes, as well as in the total spectral area. Conversely, QRS duration and 50- to 250-Hz or 70- to 110-Hz spectral areas were not significantly altered. In 14 cases mild rejection episodes were observed that did not significantly alter any of the variables studied. The root-mean-square voltage of the 70-Hz high pass filtered QRS complex was found to be the most accurate variable in detecting rejection. Moreover, this variable was also the most reproducible in 10 healthy control subjects. The optimal rejection criterion was defined as an 11% decrease in voltage between two consecutive recordings. It provided 87.5% sensitivity with 78.4% specificity. In conclusion, the signal-averaged ECG is helpful in the management of heart transplant rejection. Frequency domain analysis of the QRS complex does not increase the accuracy of the technique compared with the time domain approach.

Comparative study of encainide and disopyramide in chronic ventricular arrhythmias: a double-blind placebo-controlled crossover study.

Ten patients suffering from chronic premature ventricular complexes (greater than 60/h) were treated orally in a double-blind crossover study with encainide (50 mg three times a day) and disopyramide (200 mg three times a day), with five 7 day study periods: survey, placebo, encainide or disopyramide, washout placebo and disopyramide or encainide. At the end of each 7 day period, a 12 lead electrocardiogram, a 48 hour ambulatory electrocardiogram and a treadmill exercise test were performed. Blood levels of encainide and its metabolites and of disopyramide were measured at the end of each treatment (steady state). Drug efficacy was assessed by: 1) more than 80% reduction in the number of premature ventricular complexes per 24 hours, and 2) absence of ventricular tachycardia. Encainide was effective in four patients (complete suppression of premature ventricular complexes) and ineffective in five. One patient who showed a 92% reduction in the number of premature ventricular complexes developed sustained ventricular tachycardia after 24 hours of treatment. Disopyramide was effective in three patients (greater than 80% reduction in the number of premature ventricular complexes) and ineffective in seven patients. With encainide, the percent increase in PR, QRS and QT interval duration was, respectively: 32.7 (p less than 0.001), 30.8 (p less than 0.001) and 10.6% (p less than 0.01). With disopyramide this increase was not significant. Despite the variability of drug blood levels, a relation between blood levels and suppression of premature ventricular complexes on the 48 hour ambulatory electrocardiogram was found with encainide, but not with disopyramide.(ABSTRACT TRUNCATED AT 250 WORDS)

[AFFIRM: what we have learned ... and pending issues]. / AFFIRM: ce que nous avons appris ... et les questions en suspens.

During these last years, several therapeutic strategies trials have been performed in atrial fibrillation: the goal was to compare the rhythm control strategy (restoration and maintenance of sinus rhythm) to the rate control strategy (slowing of heart rate in atrial fibrillation). The most important of these different trials is the AFFIRM study. The main conclusion of this trial is that rate control can be chosen in first intention and not only in case of failure of the rhythm control strategy. These results can not be applied to 2 categories of patients: on one hand patients with heart failure and on the other hand young patients without cardiopathy in whom the strategy of rhythm control and sinus rhythm maintenance, mainly by class I antiarrhythmic drugs, remains the better choice.

Factors affecting epicardial dispersion of repolarization: a mapping study in the isolated porcine heart.

OBJECTIVE: Non-uniform drug-induced prolongation of repolarization predominating in the midmyocardial (M) cell layers has been shown to be responsible for perpetuation of reentry, giving rise to torsade de pointes. However, the absence of M cells in immature animals, especially the pig, suggests other possible underlying mechanisms. We sought to examine, in this species, the effects of predisposing factors to torsade de pointes on the dispersion of epicardial repolarization and their contribution to arrhythmogenesis. METHODS: Computerized mapping of repolarization and activation was conducted on the epicardial surface in 29 Langendorff-perfused hearts of eight-week-old pigs. Activation-recovery intervals were measured simultaneously from 128 unipolar electrograms. RESULTS: Baseline iso-interval maps were dipolar (41%) or multipolar (59%). Dispersion of repolarization was reverse frequency-dependent but was unaffected by lowering [K+]o. DL-Sotalol (0.1 mmol/l) reinforced local gradients and thus increased epicardial dispersion, whereas intramural recordings did not demonstrate any predominant effect in midmyocardial layers. Phenylephrine (1 mumol/l) notably augmented DL-sotalol effects. After [Mg++]o lowering, although dispersion was not significantly increased, DL-sotalol was associated with the spontaneous occurrence of polymorphic ventricular tachycardia in seven out of nine experiments. When maps of repolarization of escape beats were compared with activation maps of first arrhythmic beats, an arc of functional dissociation was observed in the vicinity of a steep gradient of repolarization in two out of nine tachycardias. CONCLUSION: Epicardial dispersion of repolarization is increased by slow rates, DL-sotalol and phenylephrine but is not the only requirement for initiation of polymorphic ventricular tachycardia. In combination with other factors, it helps continuation of the arrhythmia in this model.

Influence of clinical and hemodynamic characteristics on signal-averaged electrocardiogram in postoperative tetralogy of Fallot.

This study examines the relation between signal-averaged electrocardiographic measurements and the occurrence of spontaneous ventricular arrhythmias in 86 patients with a postoperative right bundle branch block after repair of tetralogy of Fallot; special attention was given to the influence of age, body surface area and right ventricular systolic pressure on signal-averaged electrocardiograms. Twenty-eight of the 86 patients had significant ventricular arrhythmias on 24-hour ambulatory monitoring. A positive linear correlation was found between filtered QRS duration and age at evaluation or body surface area (r = 0.45, p = 0.00001; r = 0.54, p < 0.00001, respectively) and between amplitude of the last 40 ms of the filtered QRS and right ventricular systolic pressure (r = 0.48, p < 0.001). A negative linear correlation was found between amplitude of the last 40 ms of the filtered QRS and age at evaluation or body surface area (r = -0.27, p = 0.01; r = -0.34, p = 0.002, respectively). When the age of the patients or the body surface area was considered with an analysis of covariance, the presence of ventricular arrhythmias was associated with a higher amplitude of the last 40 ms of the filtered QRS. In addition, an amplitude of the last 40 ms of the filtered QRS > 170 microV had an excellent sensitivity (100%) and a good specificity (88%) for identifying patients with both right ventricular systolic hypertension and spontaneous ventricular arrhythmia. Thus, adjustment of signal-averaged parameters for age at evaluation and body size is mandatory when studying postoperative tetralogy of Fallot.

Randomized comparison of two targets in typical atrial flutter ablation.

Typical atrial flutter ablation has become anatomically guided to 2 separate sites within the isthmus at the inferior right atrium: (1) between the inferior vena cava and the tricuspid annulus (anterior side of the isthmus [A]), (2) between the eustachian crest, the coronary sinus ostium and tricuspid annulus (posterior side of the isthmus [P]). We prospectively compared ablation results at these sites in 72 consecutive patients. Patients were randomized in group P or A according to the initial target site. If ablation failed at 1 site after 15 radiofrequency (RF) pulses, the other side of the isthmus was targeted. Before 15 RF pulses, complete bidirectional isthmus block was achieved in 30 of 36 group A patients and in 25 of 36 group P patients, with similar mean RF pulses number, procedure time, and fluoroscopy time. After shifting to the other target, success was finally obtained at P in 2 of 6 group A patients, and at A in 8 of 11 group P patients before a maximum of 30 RF pulses. Among successful patients, number of RF pulses, procedure time, and fluoroscopy time were significantly lower in group A (7.2 +/- 5.4 vs 11.0 +/- 8.1 pulses, p = 0.03; 131 +/- 44 vs 163 +/- 66 minutes, p = 0.03; 31 +/- 19 vs 46 +/- 24 minutes, p = 0.01, respectively). Impairment of atrioventricular (AV) nodal conduction occurred in 5 patients only during ablation at P. AV block was transient in 4 patients and permanent in 1. Although atrial flutter ablation is equally effective at P and A, success seems easier to obtain when A is first targeted. Ablation at P is associated with a significant risk of AV block.

Extraction of endocardial implantable cardioverter-defibrillator leads.

Despite a growing number of implantable cardioverter-defibrillator (ICD) lead removal indications, there is no consensus about extraction techniques. We applied our experience of pacemaker lead removal to ICD leads using a superior approach with a standard extractor kit, and an inferior approach with a lasso, or a surgical extraction. Fifteen leads were removed in 11 patients during 12 procedures (1 patient was referred twice): 11 right ventricular defibrillation leads, 3 right atrial coils, and 1 atrial lead implanted with a DDD-ICD. The indication for lead extraction was insulation failure (n = 4), conductor fracture (n = 2), abdominal pocket infection (n = 4), lead endocarditis (n = 1), and replacement of an atrial coil by an atrial lead for DDD-R pacing (n = 1). One patient had surgical extraction of 2 leads because of an endocarditis with large vegetations on a DDD-ICD. In 11 other cases, 5 leads were removed using a superior approach with a standard extraction kit and 8 leads were removed by a femoral approach using a lasso alone or added to a pigtail catheter. There was no failure of explantation. One extraction attempt failed with the superior approach but was successful with a secondary inferior approach. The main difficulties encountered were due to tight adherence of the proximal coil to the venous wall and to dislodgment of passive fixation leads from their endocardial insertion. One patient had subclavian vein thrombosis after intervention; no major complication was noted. Ten patients immediately underwent reimplantation. Two patients (1 with an endocarditis and 1 free of ICD therapy for 5 years) did not have reimplantation. During a 4- to 44-month follow-up, no late complication appeared. Thus, ICD lead explantation can be performed with a good success rate, with extraction techniques similar to those used for pacemaker leads.

Ventricular tachycardia originating from the posteroseptal process of the left ventricle with inferior wall healed myocardial infarction.

Ventricular tachycardia (VT) substrates may form in preferential locations and similar electrocardiographic patterns may be observed when ventricular activation starts from a particular site. We examined the role of the posterior inferior process of the left ventricle in the mechanism of VT occurring after inferior wall myocardial infarction. We reviewed isochronal maps of 40 VTs obtained at surgery in 13 patients, with a 128-electrode system using epicardial sock and endocardial balloon electrode arrays. Based on the epicardial to left endocardial relation we observed 7 tachycardias in 7 patients with onset of activation over the crux of the heart. This activation mimicked excitation through a posteroseptal accessory pathway. Endocardial activation maps showed breakthroughs occurring 6 to 40 ms later and did not give evidence in favor of macroreentry. In all but 1 VT, left-axis deviation was present (-30 to -75 degrees) with a positive concordance from leads V2 to V6 (QRS wave patterns were variable in V1). These tachycardias, which were clinical in 3 of 7 cases, were interpreted as arising from the posterior inferior process of the left ventricle and successfully ablated by left septal and epicardial cryolesions. In another patient, this concept was further validated by percutaneous radiofrequency ablation of a tachycardia with the previously described morphology. In conclusion, VT may originate from the posteroseptal process of the left ventricle with inferior wall healed myocardial infarction. Because these tachycardias can be successfully eliminated, their characteristic morphologies may provide clinical markers for the identification of patient candidates to surgical or nonsurgical ablative therapy.

Biventricular pacing in patients with congestive heart failure: two prospective randomized trials. The VIGOR CHF and VENTAK CHF Investigators.

Epidemiologic studies suggest that 20-30% of patients diagnosed with symptomatic congestive heart failure (CHF) have intraventricular conduction disorders characterized by a discoordinate contraction pattern and wide QRS. Biventricular pacing is an emerging therapy allowing simultaneous electrical stimulation of the right and left ventricles with the use of an implantable pacing system. The aim of this article is to describe 2 prospective randomized multicenter trials examining the effects of biventricular pacing on functional capacity, quality of life, and hemodynamic status in patients with dilated cardiomyopathy and intraventricular delay. The VIGOR CHF Trial is designed to assess functional and symptomatic improvement in heart failure patients with biventricular pacing and without a concomitant indication for conventional bradycardia pacemaker therapy. To assess for potential placebo effects, patients are randomized to receive either biventricular pacemaker therapy or no pacing therapy for the first 6 weeks, after which both groups receive pacing therapy. The VENTAK CHF trial uses an implantable cardioverter defibrillator system (ICD) designed to provide chronic biventricular pacing therapy in addition to treating ventricular tachyarrhythmias. All patients receive conventional ICD and CHF therapy throughout the study and are randomized in a 2-period crossover design to receive either no pacing or biventricular pacing for 3-month intervals. Patient enrollment in both studies is ongoing, with a closed analysis. The unique designs of these trials provide the opportunity to study this therapy in high-risk patients who have been optimally treated for heart failure.

Acute electrophysiological effects of intravenous milnacipran, a new antidepressant agent.

Milnacipran is a new antidepressant agent selected from a series of cycloproprane derivatives. The aim of this study was to investigate the acute electrophysiological effects and the tolerance of intravenous administration of this drug in 10 patients without any abnormality as shown in an electrophysiological study done for various complaints. Milnacipran was given over a 30-min period at doses of 0.2 mg/kg (2 patients), 0.4 mg/kg (2 patients) and 0.8 mg/kg (6 patients). The most significant alterations observed in this study were increases in heart rate (average of maximal increase: +19.5% at 50 min, P = 0.06) and systolic blood pressure (average of maximal increase: +21.5% at 10 min, P < 0.005), and decreases in the functional refractory period of the atrium (-3%, P < 0.05), the atrioventricular node (-9%, P < 0.005) and the effective refractory period of the right ventricle (-10.8%, P < 0.05) at 50 min. The sinus node function was improved in nine patients but depressed in one patient with previous slight baseline sinus node alterations. Milnacipran being devoid of both anticholinergic and monoamine oxidase inhibition activities, these alterations could be related to inhibition of noradrenaline uptake leading to an increase of adrenergic activities. No other ECG or electrophysiological parameters were significantly altered. Five of the 10 patients reported transient nausea, four of them for the highest dosage (0.8 mg/kg) and at the moment of peak of milnacipran plasma level. In conclusion, electrophysiological effects of intravenous milnacipran are negligible. These findings differ from those, well described in the literature, for imipramine-like antidepressant agents.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasospastic angina without flow-limiting coronary lesions as a cause for aborted sudden death.

Two patients resuscitated from out-of-hospital cardiac arrest were later found to have minor coronary atherosclerosis and no inducible ventricular arrhythmia. Coronary spasm was not elicited during provocative tests but occurred on introduction of the catheter in the right coronary artery and spontaneously recurred after resuscitation, leading to myocardial infarction in one patient. Both patients received an implantable cardioverter defibrillator and subsequent discharges, while receiving calcium antagonists.

Single radiofrequency application to cure atrioventricular nodal reentry: arguments for the slow pathway origin of the high-low frequency slow potentials.

BACKGROUND: High-low frequency slow potentials are thought to be related to the slow AV pathway conduction. Their use was proposed to guide radiofrequency (RF) ablation of atrioventricular nodal reentrant tachycardia (AVNRT). The present study was designed to determine the prospective value of these high-low frequency slow potentials to guide AVNRT ablation using a single RF application. Single RF application could indeed reduce the size of the lesion created in the viciny of the specialized AV conduction system and shorten the radiation exposure and the overall duration of the procedure. RESULTS: Forty-one patients (14 men, 27 women, 45 +/- 16 years old) with AVNRT underwent slow pathway RF ablation guided by high-low frequency slow potentials. High-low frequency slow potentials were found in all patients along the tricuspid annulus and above the coronary sinus. Ablation was always performed in the posterior part of Koch's triangle. The mean A/V amplitude ratio of the successful site was 0.43 +/- 0.59. In 32 patients (78%) AVNRT was no longer inducible after a single RF application. Procedure and radiation times were 35 +/- 31 and 13 +/- 12 min respectively. Five patients required 2, 3 patients 3, and 1 patient 6 RF applications. The mean number of RF applications was 1.4 +/- 0.9 (median = 1). In the 32 patients who required only one RF application, 24 (75%) had an obvious dual AV nodal pathways with a jump before ablation, which completely disappeared in 18 of them (75%) after ablation. In the 6 remaining patients, who still had a jump after 1 RF application, there was no significant change in either conduction times or refractory periods concerning both the anterograde and retrograde AV conduction. No patient had PR interval purlongation. After a mean follow up of 11 +/- 5 months, recurrence was observed in a single patient who received 2 discontinued RF applications. CONCLUSION: Catheter-mediated ablation of AVNRT using high-low frequency slow potentials to localize the slow AV pathway is feasible and safe. Using this technique, a single RF application was successfull in 78% of patients, and slow pathway characteristics were completely eliminated in 75% of patients. The radiation time and the procedure duration were short. This suggest that, in patients with AVNRT, the choice of an appropriate RF target can reduce procedural duration.

Comparative cardiac effects of intravenous bolus of ipratropium bromide (itrop) and atropine sulfate in 22 patients.

At the present time, there is no satisfactory pharmacological treatment for arrhythmia or conduction disorders induced by or aggravated by vagal hypertonia. The limited duration of action of the atropine derivatives currently available justifies the development of new compounds with expected longer acting duration. The aim of this study was to compare the effects of a single blind intravenous injection of ipratropium bromide to those of atropine sulfate in 22 patients. These patients were studied with continuous Holter recordings for three days. During the second and the third nights (patient sleeping), boluses of atropine (0.03 mg/kg) and of ipratropium bromide (0.03 mg/kg), respectively, were added to a continuous saline intravenous infusion. Accurate ECG analysis allowed determination of maximal heart rate peak, timing of maximal heart rate, variations in sinus cycle length, atrioventricular conduction, and durations of drug action. A nonsuggestive questionnaire was presented to patients to detect possible occurrence of side effects. The mean maximal heart rate rose significantly (p less than 0.001) for atropine (+46.2%) and for ipratropium bromide (+57.4%). The effects obtained with ipratropium bromide on the heart rate lasted nearly twice as long as those obtained with atropine (respectively, 120 +/- 38.4 min and 70 +/- 30 min- for the pharmacological half-life). Common minor muscarinic side effects (dryness of the mouth) were noted with the two drugs. In conclusion, this comparative intraindividual study confirmed the prolonged vagolytic effects of intravenous ipratropium bromide, which may be valuable in the treatment of patients with vagally mediated automaticity and conduction disturbances.

Propafenone versus disopyramide: a double-blind randomized crossover trial in patients presenting chronic ventricular arrhythmias.

In vitro and in vivo electrophysiological studies have shown that propafenone could be classified as a class I antiarrhythmic agent. The aim of this study was to investigate the short-term antiarrhythmic efficacy and safety of propafenone in 10 patients compared to disopyramide in a double-blind randomized protocol. Included patients suffered from ventricular arrhythmias with at least 60 ventricular premature beats (VPB) per hour refractory to at least two other antiarrhythmic agents. At the end of the control period and of the two treatment periods during which patients received either propafenone (300 mg three times a day) or disopyramide (200 mg three times a day), clinical examination, Holter recordings, electrocardiogram, and clinical laboratory tests were performed. The PR interval and the QRS interval were significantly increased with propafenone, but not with disopyramide. The cQT interval was not significantly changed by either propafenone or disopyramide. Heart rate was decreased with propafenone (p less than 0.05) with no change in the diurnal/nocturnal circadian ratio variation. Heart rate was significantly decreased with disopyramide only during the day. Five of nine patients in the propafenone group and two of nine patients in the disopyramide group showed a reduction in ventricular premature beats greater than 80%. Total resolution of severe arrhythmias (repetitive events) was seen in 5 of 8 patients with propafenone; 2 of 8 with disopyramide. Adverse events, when they occurred, were mild (visual disturbances, epigastric discomfort, changes in taste perception, transient atrioventricular block with propafenone, and photophobia with disopyramide), and did not require reduction or discontinuation of study drug.(ABSTRACT TRUNCATED AT 250 WORDS)

[New concepts of anticoagulant therapy of atrial fibrillation]. / Nouveautés dans le traitement anticoagulant de la fibrillation auriculaire.

The news concerning anticoagulant therapy is very rich. It was also keenly awaited in view of the real imperfection of antivitamin K drugs on which the present strategy of prevention of thromboembolic risk related to atrial fibrillation is based. The new anticoagulants have differing targets identified from the physiological mechanism of coagulation and the physiopathology of thrombosis.

[Thromboembolic complications of arrhythmia due to atrial fibrillation]. / Complications thrombo-emboliques de l'arythmie complète par fibrillation auriculaire.

Fifteen per cent of cerebrovascular accidents have a cardiac origin, two thirds of which are due to atrial fibrillation (AF). The Framingham study showed the risk of an ischaemic cerebral event to be increased by 5.6 in AF unrelated to rheumatic heart disease and by 17.5 when AF is associated with valvular heart disease. The risk of embolism is higher in elderly subjects and in those with underlying cardiac disease. Other high risk conditions include hypertension, diabetes, hyperthyroidism and cases with echocardiographic changes: left atrial dilatation, pre-thrombotic state or intra-atrial thrombus, atheroma of the ascending aorta. This stratification of risk should be taken into account when deciding on treatment. Conscious of the importance of the risk of embolism in AF, several authors have undertaken, over the last few years, randomised studies of the prevention of thromboembolic complications of AF: the AFASAK, BAATAF, SPAF and SPINAF trials. All showed the unquestionable efficacy of warfarin, even at low doses, at the price of a haemorrhagic risk of less than 2% per year for severe haemorrhages. A more recent study (SPAF II) confirmed the value of aspirin at the dosage of 325 mg/day which would seem to be a good alternative to anticoagulant therapy when this is contraindicated, although aspirin is less effective. The indications for anticoagulant therapy have become clearer since the publication of these results. Anticoagulant therapy is essential in permanent AF whether or not associated with rheumatic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

[Interference between cardiac pacemaker and electromagnetic anti-theft devices in stores]. / Interférences entre les stimulateurs cardiaques et les détecteurs de vol dans les magasins.

Electromagnetic anti-theft devices in shops comprise large diameter magnetic induction coils between which the shoppers pass. This study was undertaken with a simulator to assess the behaviour of different models of single and double-chamber pacemakers when exposed to 6 stereotyped and repetitive situations of 4 different electromagnetic anti-theft devices. Of the 35 pacemakers tested, 25 developed serious dysfunctions: 14 long-lasting inhibitions (over 3 seconds), 2 stimulations at maximal frequency, 2 electrical bradycardias and 2 permanent reprogramming. These dysfunctions due to electromagnetic interference are observed in old or modern, monopolar or bipolar pacemakers, and seem to be influenced by the amplitude and complexity of the signals emitted by the detectors. These observations justify a clear signalization warning pacemaker patients of a potential danger.