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Sudden death during sport is a rare and unexpected event. It essentially affects young males, and a cardiomyopathy that had not been diagnosed during medical examinations is present in the majority of cases. In young subjects, there is generally hypertrophic cardiomyopathy or arhythmogenic right ventricular dysplasia. This is revealed during sporting activity, and sudden death is often the first symptom of the disease. Competitive sport increases the relative risk of sudden death to 2.5 compared to the risk in a non-sporting subject. The prevalence of sudden death during competitive sport is poorly understood. From the rare studies available, it could be estimated at 2.3/100,000 athletes per year. In Europe, it essentially occurs during football matches. However, the prevalence of sudden death during so-called 'recreational' sports is not precisely known. It could be much higher because these activities involve a larger number of people, and take place without supervision and usually without a medical examination beforehand. The participants are older, and coronary pathology is usually implicated.

Unlabelled: Brugada syndrome is a recently identified cause of sudden death. Its primary prevention remains controversial, and epidemiology poorly defined., Patient Population and Methods: Electrocardiograms (ECG) of 35,309 individuals (mean age = 37.2 years, 47% men) recorded over a 1-year period were reviewed and classified as (1) typical, (2) suspicious, and (3) negative. Subjects whose ECG was suspicious were offered a provocative test with flecainide, 2 mg/kg, i.v., and individuals whose ECG was typical were advised to undergo programmed ventricular stimulation (PVS)., Results: In 14 men and 6 women between the ages of 24 and 77 years (mean =47.5), ECGs were typical (n=6) or suspicious (n=14). Among 6 subjects with typical ECGs, 3 underwent PVS, which was positive in 1, who received an implantable cardioverter defibrillator (ICD). Among 14 subjects whose ECGs were suspicious, 5 declined further investigations and 5 developed typical ECG characteristics of Brugada syndrome after flecainide administration. PVS was negative in 4 subjects who consented to the procedure. Overall, among 35,309 individuals screened, 11 had ECG findings consistent with Brugada syndrome and, over a follow-up of 30 months, all had remained free of adverse cardiac event., Conclusions: we estimated a prevalence of Brugada syndrome of 0.3% in Lorraine. A single patient received an ICD for inducible ventricular tachyarrhythmia during PVS, representing a potential 30 per million asymptomatic adult rate of ICD implantation for this indication.

The electrocardiogram, as much as the clinical examination, is a basic tool for the cardiologist. Technological advances have led to a certain lack of interest in learning to read the electrocardiogram, for which close analysis can allow precise diagnosis, notably in the field of cardiac rhythm disorders. This article concerns the electrocardiogram in ventricular tachycardias with two themes: differential diagnosis of wide QRS complex tachycardias and recognition of the site of origin of a ventricular tachycardia. "Fine" analysis of the electrocardiogram is not an intellectual "game". Actually, careful analysis of the 12 lead ECG allows exact and rapid diagnosis in a large majority of cases, distinguishing a ventricular tachycardia from a supraventricular tachycardia with conduction defect; the appropriate management can be selected without delay. At the same time, close reading of the electrocardiogram also allows the site of origin of a ventricular tachycardia to be recognised. Combining this information with elements of the patient's record can allow the arrhythmia to be related to a known pathology or to prompt a targeted aetiological investigation.

The indications of radiofrequency ablation of arrhythmias have considerably increased since the introduction of the technique in the early 1990s. Interventional rhythmologists now treat arrhythmias which are more and more complex by their mechanism. This requires accurate representation of the ablation catheter position and the integration of spatial and temporal data to identify the arrhythmogenic substrate. The systems of mapping and navigation developed over the last ten years are important tools for interventional rhythmologists. They are very useful for the identification of complex arrhythmogenic substrates which require "individualised" ablations in specific cases. The aim of this article is to review different systems of mapping, and/or navigation currently on the market and their principal characteristics without entering into the details of their use in interventional electrophysiology.

Unlabelled: The implantable automatic defibrillator has proved its superiority over pharmacological treatments for preventing mortality by serious ventricular arrhythmia. We studied the cause of death in a population of 283 consecutive patients implanted between February 1988 and December 2000 (age at implantation: 58 +/- 14.7 years; extremes: 15-78 years, 45 females, ejection fraction: 0.39 +/- 0.15) and followed up over a median of 25 months (extremes = 1 day-163 months)., Results: At the end of follow up, 55 patients had died (average age: 62.7 +/- 12.6 years, extremes: 15-79 years, 7 females). All except 2 had a cardiopathy: ischaemic cardiopathy (n = 38, 36 IDDM), dilated cardiomyopathy (n = 14), arrhythmogenic dysplasia of the right ventricle (n = 1). The median interval between implantation and death was 35 months (extremes = 1 day-137 months). The causes of death were the following: cardiac insufficiency (n = 24), refractory arrhythmias (n = 13), other cardiac causes (n = 8), extra-cardiac pathologies (n = 10). The deceased patients had presented an average of 86.6 +/- 23.4 ventricular arrhythmias (extremes = 0-1309) but 18 of them (33%) did not present any during follow up., Conclusions: Cardiac insufficiency is the prime cause of death in refractory arrhythmias; on patient in 4 dies from ventricular arrhythmia, despite the defibrillator and one deceased patient in 3 had no arrhythmia during follow up.

The aim of this study was to report the authors' experience of radiofrequency ablation of accessory atrioventricular pathways over a 10 year period (01-91 to 10-00), and the effect of the "learning curve" on the results. The data of 400 patients admitted to primo-ablation of a bundle of Kent was analysed retrospectively. A total of 481 ablations were performed (1.20 per patient). The cumulative global success in the 414 accessory pathways treated was 90.6%. The primary success rate increased from the 1st to the 4th quartile from 68 to 97% (p = 0.0001). The mean duration of fluoroscopy and number of ablation sites decreased from the 1st to the 4th quartile respectively from 47 +/- 27 to 25 +/- 18 minutes (p = 0.0001) and from 8.5 +/- 7.8 to 4.5 +/- 3.8 minutes (p = 0.0001). The average recurrence rate over the four quartiles was 3.6. The overall complication rate was 1.44%. The improved primary success rate from 1991 to 2000 and, in parallel, the reduction of the number of inappropriate ablation sites and fluoroscopy duration are explained not only by the "learning curve" of our centre but also by the benefits of the application of scientific acquisitions (unipolar recordings, criteria for ablation site localisation...) and technical progress (ablation with temperature monitoring...) over this period.

Introduction: The clinical expression of Lyme disease is highly variable. If a patient presents clinical findings consistent with a systemic Lyme borreliosis, this disease must be considered in an endemic area because of its favorable outcome with adequate treatment., Exegesis: The authors report and discuss the case of a patient with an unusual history of dilated cardiomyopathy and supraventricular fibrillation followed by bilateral panuveitis. Enzyme-linked immunosorbent assay and Western blot were positive for Borrelia burgdorferi antigens. The diagnosis of Lyme disease was made after other infectious, inflammatory and autoimmune disorders were excluded by clinical, instrumental and biological investigations. The treatment by ceftriaxone and amoxicillin resolved the ophthalmologic manifestations and improved the cardiac condition., Conclusion: This report underlines the possibility of an unusual presentation of Lyme disease. Ophthalmologic and cardiac involvement should be known by clinicians.

Hypertrophic cardiomyopathy (HCM) is defined as primary hypertrophy of the heart muscle, usually the left ventricle which is not dilated. HCM is a relatively common disease with a prevalence estimated at about 1 in 500. It is a complex disease with relatively stereotypical anatomical features but a very variable clinical presentation with a major risk of complication. All forms may be observed from almost asymptomatic hypertrophy to severe familial forms with multiple cases of sudden death. Over the last few years, molecular studies of the genetic abnormalities responsible for HCM have improved our understanding of the clinical variability of this disease. Schematically, HCM is caused by mutation of one of 4 genes which code the proteins of the sarcomere: the gene of the heavy chain of beta-myosin, the gene of cardiac T-troponin, the gene of alpha-tropomyosin and the gene of protein C linked to cardiac myosin. The main problem for clinicians is not making the diagnosis, which is relatively simple by echocardiography, but to assess the risk of complications, especially in adolescents and young adults. Patients over 40 to 45 years of age pose fewer problems as their disease is generally associated with a better prognosis since they have already survived to that age. There are many prognostic factors of sudden death, a reflection of the multifactorial character of sudden death in this disease. Four major risk factors have been identified: a family history of sudden death, abnormal blood pressure changes on exercise, a history of syncope and non-sustained ventricular tachycardia on 24 or 48-hour Holter monitoring. In children and adolescents, only the first three factors may be used, knowing that syncope, though rare, carries a very poor prognosis. On the other hand, in adults up to 40, all 4 factors are valid. Unfortunately, their positive predictive value is relatively poor, all the patients with one of these risk factors not automatically experiencing sudden death. On the other hand, their negative predictive value is excellent. Therefore, a patient with none of these factors has an excellent prognosis and should be allowed to lead a normal life. The risk is considered to be high when 2 or 3 of the factors are associated, theoretically justifying aggressive management (amiodarone? defibrillator?). Finally, there is no established management protocol in cases with a single risk factor. The discovery of mutations causing HCM will probably open up new methods of assessing the risk of sudden death in this disease. It would seem to be possible to assess the impact of the genotype on prognosis. However, this "genetic stratification" remains the realm of top research teams and is not yet accessible routinely in clinical practice.

The aim of the study was to compare the value of different modes of endocavitary recordings: unipolar alone, bipolar alone and the association of unipolar and bipolar recordings in radiofrequency ablation of accessory atrioventricular pathways. A retrospective analysis by three independent observers of 135 endocavitary recordings obtained immediately before radiofrequency application in 82 subjects who underwent radiofrequency ablation for symptomatic accessory atrioventricular pathways. In each case, the authors selected the "successful" record which corresponded to the final radiofrequency application and 0.1 or 2 records of "failures". Each initial recording being of 3 types (unipolar, bipolar and association of uni- and bipolar), a total of 390 anonymous and randomised recordings were analysed by the observers who determined whether the appearances indicated successful ablation. Univariate analysis of variants showed a correlation between success with the mode of recording (p = 0.03) and a left lateral position of the accessory pathways. In multivariate analysis, three variables remained correlated with successful ablation: the observer variable (p = 0.001), and two interactions observer - mode (p = 0.005) and observer-stability (p = 0.02). The benefits of the association of unipolar and bipolar recordings with respect to bipolar recording alone, seemed to be important in predicting failure. The results of tests of concordance in the group of failures were confirmatory: concordance between observers was only found between the unipolar mode alone and the association of unipolar and bipolar recordings. The results of this study suggest that the association of unipolar and bipolar endocavitary recordings may reduce the number of unnecessary application of radiofrequency energy by improved identification of recording showing failure.

Radiofrequency catheter ablation has become the treatment of choice of arrhythmias related to accessory atrioventricular pathways. The reported success rate is well over 90%, irrespective of the localisation of the accessory pathway, and serious complications are rare. A basic principle of the technique is the limitation of the number of applications of radiofrequency energy during a session of ablation and this requires mapping to determine the ideal site using various electrographic parameters. With regards to bipolar recordings, they include: the atrioventricular conduction time, localisation of the ventricular pole of the accessory pathway, recording the accessory pathway potential, the atrial pole of the accessory pathway, and stability of the catheter position. However, the parameters are not readily reproducible and the positive predictive value for successful ablation is low. The use of unipolar electrograms could therefore represent a fundamental step in improving the localisation of accessory pathways and thereby reducing the number of useless applications of radiofrequency energy.

The aim of this study was to search for the presence of atrial vulnerability by programmed atrial stimulation in patients with unexplained ischaemic cerebrovascular strokes and to evaluate the effects of intravenous flecainide acetate on the electrophysiological parameters and on the induction of atrial arrhythmias. Thirty-eight patients (20 men, 18 women) with a mean age of 38.4 +/- 11 years were investigated. Programmed atrial pacing triggered a sustained (> 1 min) atrial arrhythmia with 1 or 2 extrastimuli in 23 of the 38 patients (61%), in these patients, there was a significant shortening of the effective refractory periods (ERP: 193 +/- 23 vs 218 +/- 30 ms; p < 0.02) and of the functional refractory periods (FRP: 228 +/- 25 vs 253 +/- 27 ms; p < 0.01) with lengthening of the A2 auriculogramme (99.7 +/- 22 vs 76.1 +/- 16 ms; p < 0.05). A combined study of the refractory periods and conduction defects provides a means of calculating an index of latent vulnerability which is greatly shortened when an atrial arrhythmia is induced (2 +/- 0.5 cm vs 3 +/- 0.6 cm; p < 0.001). Atrial arrhythmias could not be initiated after intravenous 3 mg/kg of flecainide acetate in 4 subjects (17%) with initially positive atrial stimulation tests. This study confirms the high frequency of atrial vulnerability in patients with unexplained ischaemic cerebrovascular strokes. In their population, the authors observed a low efficacy of flecainide acetate in the prevention of reinduction of atrial arrhythmias. The indication of long-term antiarrhythmic drugs in these patients are questionnable and should be assessed by a prospective long-term multicentre trial.

A lot of acquired data concerning the prognostic factors of post-infarction mortality dates from the pre-thrombolysis era. This mortality has considerably decreased since the active management of the acute phase of myocardial infarction. This has made it more complex to evaluate the post-infarction electrical risk and may have reduced the need. However, it is not less true that the assessment of the post-infarction risk necessitates a study of each factor predisposing to severe ventricular arrhythmias and sudden death: myocardial ischaemia, left ventricular dysfunction and electrical instability. The latter parameter may be assessed by non-invasive (ventricular extrasystoles, late ventricular potentials, heart rate variability, the baroreflex and the QT interval) and invasive methods (programmed ventricular stimulation). The association of these results has an excellent negative predictive value, and also improves the positive predictive value which, nevertheless, remains insufficient for expensive prophylactic measures associated with a certain morbidity, for example the implantation of a defibrillator device, to be taken.

The rapidity of technological progress has now made available a device which was only a dream a few years ago, a nearly ideal implantable defibrillator. Despite the persistence of a number of technical and clinical problems, the fourth generation defibrillators are multiprogrammable, with antitachycardia and antibradycardia functions, implantable by the endocavitary approach in most cases thanks to the introduction of biphasic shocks, fitted with constantly improving systems of telemetry, and are progressively smaller in size. The selection of a defibrillator device requires consideration of the patient's needs and the technical characteristics of the defibrillator. Apart from special situations in which the indications of the implantable defibrillator are generally accepted, it is only possible in the absence of results of prospective clinical trials, to use data accumulated on the place of defibrillation compared with other forms of management of severe ventricular arrhythmias. As there is a wide choice of treatment of these ventricular arrhythmias, the role of each must be defined for each individual patient. With regards to the implantable defibrillator, it is essential to take into consideration a number of clinical and paraclinical factors such as the clinical preservation of the arrhythmia, the underlying cardiac disease, left ventricular function and the type of arrhythmia induced by programmed ventricular stimulation.

This retrospective study reports the immediate and long-term results of percutaneous ablation of atrioventricular conduction. Between July 1983 and January 1992, 85 consecutive patients (51 men, age 64 +/- 10 years, range 43-84 years) presenting with supraventricular arrhythmias (atrial fibrillation n = 53; atrial flutter n = 50; atrial tachycardia n = 17; junctional tachycardia n = 6) resistant to antiarrhythmic therapy (number of drugs used: 4 +/- 1.3, range 1-6) underwent interruption of atrioventricular conduction by fulguration (n = 65) or radiofrequency energy (n = 13) or by an association of the two methods (n = 7). The 75 pacemakers implanted (10 patients had pacemakers before the procedure) comprised 55 VVIR, 11 VVI, 5 DDD and 4 DDDR units. The immediate results included two sudden deaths at the 4th and 7th day in patients undergoing fulguration and three complications with a favourable outcome (staphylococcal septicaemia, pulmonary embolism and haematoma at the site of implantation of the pacemaker). None of the patients was lost to follow-up and the average follow-up was 31 +/- 18 months (range 2-108 months). During follow-up, 15 patients died and there was a recurrence of symptoms in 11 patients after 1 to 9 months requiring a repeat procedure. In the 68 survivors, the follow-up is now 38 +/- 18 months (range 12-108 months). Sixty one patients have 2nd (2) or 3rd (59) degree atrioventricular block, giving 90% good electrocardiographic results.(ABSTRACT TRUNCATED AT 250 WORDS)

The authors report their experience of long-term dual-chamber pacing in the treatment of hypertrophic and obstructive cardiomyopathy. Between August 1990 and March 1993, 16 patients (8 men, average age 53.5 +/- 18.9 years, range 21 and 79 years) with symptomatic hypertrophic obstructive cardiomyopathy resistant to medical therapy underwent electrophysiological investigation to assess atrioventricular conduction and the effects of temporary atrioventricular pacing on the intraventricular pressure gradient before implantation of a dual-chamber pacing system. The decision to implant was taken if the endocavitary studies showed severe atrioventricular conduction defects and/or if temporary pacing reduced the systolic pressure gradient by more than 30%. Temporary dual-chamber pacing led to a decrease of 48% of the systolic pressure gradient from 78.6 +/- 21.3 to 40.1 +/- 23.6 mmHg (p < 0.0005), a regression observed in 15 of the 16 patients. After an average follow-up period of 18.7 +/- 9.5 months (range 6 and 37 months), all 15 patients who received a dual-chamber pacing system were alive and were clinically improved. The systolic pressure gradient continued to decrease during the follow-up period (24.4 +/- 17.2 mmHg at the 6th month compared with 36.5 +/- 18.6 mmHg at the time of implantation; p = 0.014). The clinical improvement was dependent on careful adjustment of the atrioventricular delay which was programmed at relatively short values (65.6 +/- 14 ms, range 47 and 75 ms) to obtain permanent right ventricular capture. The authors conclude that dual-chamber pacing is an effective means of treating symptomatic hypertrophic obstructive cardiomyopathy resistant to medical therapy, even in the absence of preexisting conduction defects.

The aim of this study was to determine the influence of electrocardiographic and biomorphometric factors on the parameters measured by signal averaged electrocardiography (SA-ECG) in normal subjects. The study population comprised 40 Caucasian students (20 men, 20 women). The SA-ECG measured 6 parameters: total duration of the averaged QRS, the root mean square of the voltage of the last 40 ms of the QRS (RMS 40) and the length duration of the terminal signal of under 40 microV (LAS), each parameter being measured with a band pass filter of 25 and 40 Hz. The echocardiographic recording included measurement of 12 parameters including left ventricular mass and ventricular volumes. Five morphological parameters were measured, including height, weight and body surface area. The duration of QRS measured with a 25 Hz band pass filter was significantly longer by 9.7 ms in men than in women (102.9 +/- 8.5 ms versus 93.2 +/- 8.1 ms; p < 0.001). Similarly, QRS duration measured with the 40 Hz band pass filter was longer in men by 11.4 ms than in women (102.1 +/- 9.6 ms versus 90.7 +/- 7.5 ms; p < 0.001). Multiple linear regression analyses showed that in both men and women, the duration of the QRS measured with either a 25 or 40 Hz band pass filter was correlated to size: the taller the subject, the longer the QRS duration. A negative correlation was observed between size and RMS 40 measured with both 25 and 40 Hz band pass filters: the taller the subject, the smaller the value of RMS 40.(ABSTRACT TRUNCATED AT 250 WORDS)

Although interruption of atrioventricular conduction has been widely used over the last decade in patients with supraventricular arrhythmias and rapid conduction resistant to antiarrhythmic therapy, the incidence of atrioventricular block obtained by delivering the energy at the tricuspid ring ranges from 45 to 92%. Failure of this technique is usually related to the inhability to record endocavitary electrogrammes compatible with probable success by the right-sided approach. The authors report four cases of interruption of atrioventricular conduction in 4 men (average age 61.5 +/- 10 years) by the retrograde arterial catheterisation after one or more (1 to 3) failures by the right-sided approach. After arterial puncture, the ablation catheter is positioned against the interventricular septum below the aortic cusps to record the His bundle electrogram. His bundle ablation was obtained after an average of 2 radio frequency energy applications (range 1 to 3). At the time of effective application, the average amplitude of the endocavitary electrogram was as follows: auriculogram 0.09 mV (range 0.05 to 0.2 mV), His bundle electrogram 0.19 mV (0.15-0.22 mV), ventriculogram 1.36 mV (1.0 to 1.7 mV). No complications were observed. After an average follow-up of 4 months, the 4 patients were still in complete atrioventricular block. This preliminary series shows that left-sided interruption of atrioventricular conduction is effective and safe. It may be proposed after failure of a right-sided attempt.

The authors report their experience of implantable defibrillators over a 5 year period. Between February 1988 and July 1992, 36 patients (25 men, 11 women, average age 51 +/- 11 years, range 18 +/- 71 years) underwent implantation of an automatic defibrillator with epicardial (n = 13, Group I) or endocardial leads (n = 23, Group II) without patch electrodes (n = 7), with subcutaneous patch electrodes (n = 12) or epicardial patch electrodes (n = 4). Three serious early complications were observed: 2 cardiogenic shocks in Group I, one of which died on Day 1 and one case of infection which required explanation of the defibrillator on Day 23 in Group II. Late complications in Group I included one case of disactivation of the defibrillator, 2 losses of output, one of which required replacement of the defibrillator and 2 increases of threshold treated by implantation of an endocardial lead. In Group II, 2 patients had inappropriate shocks due to overdetection (n = 1) and double counting (n = 1). During an average follow-up period of 28.5 +/- 9 months in group I and 13 +/- 6 months in Group II, 4 patients died, 2 from sudden death. Ninety seven shocks were delivered in 19 patients (56%), 5.1 shocks per patient. In the 17 patients with an antitachycardia function, 14 (82%) developed 947 episodes of VT treated successfully by antitachycardia pacing in 917 cases. This retrospective study confirms the efficacy of implantable defibrillators in the treatment of malignant ventricular arrhythmias. The efficacy of endocardial and epicardial leads seems to be the same but there seems to be a lower immediate mortality and morbidity with the endocardial system.

The presence of late ventricular potentials and the induction of sustained ventricular tachycardia (SVT) by programmed ventricular stimulation (PVS) after myocardial infarction are markers of the risk of serious ventricular arrhythmias. The authors studied the value of signal averaged electrocardiography (SAECG) compared with induction of SVT by PVS in 118 consecutive patients 4 to 8 weeks after myocardial infarction. In addition to this study population, a control group of 22 patients with spontaneous SVT after myocardial infarction was also considered. Three parameters were measured after averaging 200 QRS complexes: the duration of the filtered QRS complex (QRSd), the duration of signals not exceeding 40 microV (LAS) and the root mean square of the voltage of the last 40 milliseconds (RMS). Abnormal values were defined as: QRSd > or = 120 ms, LAS > or = 39 ms, RMS < or = 20 microV. Patients in the study population were subdivided into 3 groups: Group I (n = 17) inducible SVT; Group II (n = 72) no inducible arrhythmias; Group III (n = 29) induction of sustained ventricular flutter or primary ventricular fibrillation requiring immediate cardioversion. The results showed a good correlation between SAECG and induction of SVT. The sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were as follows: 1) QRSd > 120 ms: Se = 82%, Sp = 80%, PPV = 41%, NPV = 96%; 2) LAS > 39 ms: Se = 59%, Sp = 85%, PPV = 38%, NPV = 92%; 3) RMS < 20 V: Se = 59%, Sp = 88%, PPV = 43%, NPV = 93%.(ABSTRACT TRUNCATED AT 250 WORDS)

The initiation of cardiac impulse is located in the sinus node, in the upper anterior part of the right atrium. The importance of the atrium is not only linked to the regulation of heart rate, but also to its haemodynamic function. Indeed, atrial depolarization leads to atrial contraction which can be responsible for up to 30% of cardiac output by way of ventricular filling. Supraventricular arrhythmias are related to one of the following mechanisms: abnormal automaticity, triggered activity, and reentry. Most of supraventricular tachycardias are due to a reentrant phenomenon (intranodal reentrant tachycardia, orthodromic circusmovement tachycardia, atrial flutter and atrial fibrillation). At the onset of a supraventricular tachycardia, the loss of efficacious atrial contraction as well as the increased heart rate may abruptly decrease ventricular filling. As a consequence, stroke volume is reduced, leading to a decrease in cardiac output and in arterial blood pressure, explaining that the patient may experience syncope. Usually, blood pressure reduction resumes within 30 seconds after activation of the autonomic adrenergic nervous system. In case of an underlying heart disease, the supraventricular tachycardia may lead to acute cardiac failure. When reentry is concerned, the tachycardia is going around a specific circuit. The existence of such a circuit in most of supraventricular tachycardias has led to the development of ablation therapy, the goal of which is to destroy a critical portion of the circuit hence making the recurrence of reentrant tachycardia impossible.

In the absence of autopsy studies, the etiological diagnosis of this form of ventricular fibrillation (VF) depends on the exclusion of cardiac disease by all available invasive and non-invasive diagnostic methods. Primary VF is rare and affects young adults. There are few clinical markers and published electrophysiological data indicates that sustained ventricular tachycardia or VF is unlikely to be induced by programmed ventricular stimulation. The underlying mechanism of the arrhythmia is poorly understood. However, a possible arrhythmogenic substrate has been suggested in small zones of fibrosis within normal Purkinje tissues, as encountered in some minor forms of arrhythmogenic right ventricular dysplasia. Also, the role played by the autonomic nervous system in triggering VF seems to be particularly important. Some described cases resemble curiously "torsades de pointes" with a short coupling interval. The "cardiac" prognosis of resuscitated patients is usually good. However, arrhythmic recurrences are common, and, classically, antiarrhythmic drugs are usually ineffective. The indication for implantation of an automatic defibrillator is therefore justified in patients surviving primary VF. The lack of understanding of this condition is an argument in favour of setting up a French register of patients with primary VF in order to establish its clinical features.

In a retrospective series of 18 consecutive patients (10 men, average age: 61.6 +/- 9.2 years) who underwent His bundle ablation by radiofrequency current, the authors analyzed the electrophysiological criteria predictive of complete atrioventricular block. A total of 82 radiofrequency bursts were analyzed (average: 4.5 +/- 3.1 bursts/patient) and classified as effective (N = 14, definitive atrioventricular block), ineffective (N = 55, no effect on atrioventricular conduction) or transiently effective procedures (N = 13, reversible Mobitz II atrio-ventricular block). Seven electrophysiological parameters were measured: HV interval, amplitude of atrial (A), Hisian (H) and ventricular (V) potentials, and the A/H, A/V, and V/H ratios before each radiofrequency burst. At the end of the ablation, 14 patients were in complete atrioventricular block and during the following 24 hours, a complete atrioventricular block developed in 3 other patients. The average value of the H potential was comparable in the effective and transiently effective procedures (0.28 +/- 0.20 mV and 0.27 +/- 0.19 mV respectively) and significantly higher than the same parameters in the ineffective group of procedures (0.65 +/- 0.14 mV, p = 0.008). The V/H ratio was progressively greater in effective (5.43 +/- 2.51), transiently effective (8.07 +/- 6.90) and ineffective procedure (14.32 +/- 13.35), p = 0.02; the average value of the A amplitude tended to be higher in the effective procedures (1.03 +/- 0.75 mV) and the transiently effective procedures (0.98 +/- 0.72 mV) than in the ineffective procedures (0.58 +/- 0.79 mV), p = 0.06. On the other hand, the other parameters were comparable in the three groups of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiofrequency catheter ablation is a modern radical treatment of the Wolff-Parkinson-White (WPW) syndrome. The authors report their experience of this method in 30 consecutive patients (12 women, 18 men, mean age 34.2 +/- 13 years, range 14 and 63 years) with the WPW syndrome poorly controlled by antiarrhythmic therapy in 27 out of 30 cases. An average of 10.1 applications (1-33) was necessary to suppress anterograde and retrograde conduction in 26 of the 30 patients during the first session (87% success rate). At the time of effective ablation, the average atrioventricular interval was 41 ms (35-55) and in the two patients with a retrograde Kent bundle, the average ventriculoatrial interval was 72 ms (70 and 75 ms). The average duration of the procedure was 3.5 hours (45 mins to 7 hours) with an average fluoroscopy time of 61.6 minutes (9-182 minutes). There were four complications: one pneumothorax, one subacute femoral arterial obstruction and in two patients with a left Kent bundle, one TIA which regressed within 1 hour and one hemiplegia which regressed in 24 hours. After an average follow-up period of 8.3 months (2-16 months) the 26 patients are asymptomatic without any treatment. Radiofrequency catheter ablation therefore seems to be an effective method with a low morbidity for the radical treatment of symptomatic or high risk WPW syndromes.

This paper reports the initial results of radio-frequency ablation of accessory pathways in 3 consecutive patients with left lateral bundles of Kent and indications for accessory pathway ablation. A modified Polaris catheter was used with a wide distal tip through which the radio-frequency current was delivered by a generator with an intensity of 0.5 Ampères and a potential of 50 Volts, i.e. power of 25 Watts. The appearances of ventricular preexcitation disappeared in all cases and did not reappear during follow-up of 7 to 28 days. These preliminary results are encouraging. Further studies with longer follow-up are required to confirm the safety and efficacy of this new promising technique of ablation.

Delayed or late potentials after myocardial infarction is a marker of the risk of severe ventricular arrhythmias. We looked for the factors favorising the appearance of these potentials in 208 consecutive patients (172 men, 36 women) admitted to hospital for primary myocardial infarction. Coronary angiography, evaluation of the left ventricular ejection fraction and signal averaged electrocardiography were performed in all patients who were then divided into two groups (Group I: patients with delayed potentials; Group II: patients without delayed potentials). A multivariate analysis of 7 different clinical and paraclinical parameters possibly related to delayed potentials was undertaken. The overall incidence of delayed potentials was 20%. The coronary artery responsible for the infarct was occluded in 79% of patients in Group I and 31% of patients in Group II (p less than 0.00009). The left ventricular ejection fraction was significantly lower in Group I (45.9% vs 54.5%, p less than 0.0002). The incidence of anterior infarcts was 58% in Group I and 37% in Group II (p = 0.008). These 3 factors were independent and correlated with the presence of delayed potentials. The multivariate analysis showed that the major factor was coronary occlusion with presence of delayed potentials multiplied by 6.3, whereas anterior infarction multiplied the risk of delayed potentials by 2.6 and each 10% decrease in LV ejection fraction increased the risk by 1.4.

Late potentials are an index of gravity following myocardial infarction, but there has been little investigation of the effects of fibrinolysis on their incidence. Eighty-two consecutive patients (68 men, 14 women, group men age = 55 +/- 8 years) admitted presenting with a primary infarction and who had received fibrinolytic treatment within the first four hours. Each patient was screened for late potentials, and underwent a coronary artery angiograph and determination of the left ventricular ejaculation fraction (LCEF) following the infarction. The incidence of late potentials was 38% in the patients with an occluded coronary artery (9/24) vs 12% in patients with a permeable artery (7/58) (p less than 0.02). The change in LVEF was greater if reperfusion was not achieved (47 +/- 13% vs 54 +/- 12%, p less than 0.05). This study suggests that following fibrinolysis, the incidence of late potentials is correlated with both an absence of coronary reperfusion and deterioration of left ventricular function.