[The Jervell and Lange-Nielsen syndrome. Natural history, molecular basis and clinical outcome]. / Syndrome de Jervell et Lange-Nielsen. Histoire naturelle, bases moléculaires et devenir clinique.

UNLABELLED: Data on the Jervell and Lange-Nielsen syndrome (JLN), the long QT syndrome (LQTS) variant associated with deafness and caused by homozygous or compound heterozygous mutations on the KCNQ1 or on the KCNE1 genes encoding the IKs current, are still largely based on case reports. We analyzed data from 186 JLN patients obtained from the literature (31%) and from individual physicians (69%). Most patients (86%) had cardiac events and 50% were symptomatic already by age 3. Their QTc was markedly prolonged (557 +/- 65 ms). Most of the arrhythmic events (95%) were triggered by emotions or exercise. Females are at lower risk for cardiac arrest and sudden death (CA/SD). A QTc>550 ms and history of syncope during the first year of life are independent predictors of subsequent CA/SD. Most mutations (90.5%) are on the KCNQ1 gene; mutations on the KCNE1 gene are associated with a more benign course. beta-blockers have only partial efficacy as 51% of the patients had events despite therapy and 29% had CA/SD. CONCLUSIONS: JLN syndrome is a most severe variant of LQTS, with a very early onset, major QTc prolongation, and is not well responsive to beta-blockers. Subgroups at relatively lower risk for CA/SD are identifiable and include females, patients with a QTc pound550 ms, without events in the first year of life, and with mutations on KCNE1. Early therapy with ICDs has to be considered.

[Use of transesophageal pacing for documentation of older children with accessory pathway]. / Intérêt de la stimulation oeophagienne dans les syndromes de préexcitation ventriculaire du grand enfant.

INTRODUCTION: In case of an accessory pathway, children are exposed to severe cardiac events including sudden death. Radiofrequency ablation is a standardized procedure, which can be applied to a significant number of children although complications can still potentially occur. In this context, transesophageal evaluation of the accessory pathway evaluation can be discussed. MATERIALS AND METHODS: Among 140 procedures performed in 19 years, 70 were done for accessory pathway evaluation. The preexcitation was overt in 59 children older than 5 years, which form the basis in this study. RESULTS: Anterograde refractory period was determined in 88% cases and was found<220 ms in 12 cases justifying an ablation procedure. Conversely, in case of a long refractory period (>250 ms), the ablation procedure was not performed in 8 asymptomatic cases and was postponed in 11/20 mildly symptomatic children. Transesophageal electrophysiologic study seems legitimate in asymptomatic or mildly symptomatic children. CONCLUSION: This technique is probably less useful in case of an overt preexcitation and recurrent reciprocating tachycardia requiring long-term antiarrythmic treatment. In this case, endocavitary electrophysiological study eventually followed by an ablation procedure seems the best option.

[Late atrial tachycardia after Fontan-type procedure. Cooperative study of 52 cases]. / Tachycardie atriale tardive après intervention de type Fontan. Etude coopérative de 52 cas.

The Fontan procedure has allowed to improve the outcome of complex congenital cardiopathy involving single ventricle. A better understanding of the systemic venous circulation has favored bicavo-bipulmonary derivation instead of atrio-pulmonary derivation. However, in spite of the improvement in surgical procedures, post-operative arrhythmias still occur with an increasing rate during follow-up reaching 40 to 50% of the patients in some series. We report a series of 52 patients of which 92% presented a severe atrial arrhythmia (atrial fibrillation or atrial flutter) during a 6-year follow-up. The outcome was worse in case of classic or modified Fontan (n=15) or direct dicavo-bipulmonary procedures (n=7). The non-modified Fontan group was characterized by a lower functional class (63% NYHA class I or II), more refractory atrial arryhthmias (37%), more deaths or transplanted patients (26%). Amiodarone was very effective in this context as opposed to the failure of class 1 anti-arrhythmic drugs. However, low dosage amiodarone in combination with a beta-blocker is recommended taking into account the important rate of amiodarone-induced side effects (53%). Atrial arrhythmia ablation was unsuccessful (8/10 failures). Anti-arrhythmic surgery (N=3) has been incompletely evaluated. In summary, transformation of failing Fontan procedures into bicavo-bipulmonary derivations seems to offer the best outcome at the price of a high surgical risk.

[Arrhythmias after surgery for congenital heart disease]. / Troubles du rythme après chirurgie des cardiopathies congénitales.

The improvement of surgical techniques over the last few years have made postoperative chronotropic insufficiency either by sinus node dysfunction or iatrogenic atrioventricular block less common. However, reentrant tachycardia around lines of incision or a patch may be observed. Persistent dilatation of a cardiac chamber or ventricular dysfunction are predisposing factors. Flutter-like arrhythmias occur mainly after atrial surgery (closure of atrial septal defects, Mustard, Senning or Fontan procedures). Ventricular tachycardias are observed more often after correction of tetralogy of Fallot or in patients with severe ventricular dysfunction. In fact, any type of arrhythmia may arise, especially when the lesion is operated late in childhood or in adulthood with a partial haemodynamic result (residual gradient, valvular regurgitation or ventricular dysfunction...). In this context, regular ECG follow-up should be associated with repeated Holter monitoring and exercise stress testing. From the therapeutic point of view, amiodarone remains the best antiarrhythmic drug. Radiofrequency ablation techniques represent a recent but decisive advance in the management of atrial arrhythmias.

[Our experience with flecainide acetate in resistant arrhythmias in children. Apropos of 35 cases]. / Expérience de l'acétate de flécainide dans les rythmes réciproques rebelles chez l'enfant. A propos de 35 cas.

Thirty-five patients aged 6 days to 18 years (average 7.5 +/- 5.2 years) were treated for an average period of 16 months (range 8 days to 50 months) with flecainide acetate at an average dose of 4.8 +/- 1.4 mg/kg (2.9 to 10 mg/kg) or 130 +/- 30.5 mg/m2 administered twice daily. The cardiac arrhythmia was a resistant paroxysmal junctional tachycardia due to a Wolff-Parkinson-White syndrome in 27 cases, intranodal reentry in 6 cases and a chronic reciprocating rhythm in 2 cases. Treatment was successful with complete suppression of the tachycardia in 24 cases. Partial success with a good clinical result was obtained in 4 cases and there were 7 failures, 6 due to inefficacy of the drug, and 1 because of an extracardiac secondary effect. One case of incessant junctional tachycardia was observed in a 9 month old child in whom the preexcitation disappeared. Atrioventricular preexcitation persisted in 20 out of 24 cases. The duration of the non-preexcited QRS complexes increased significantly from 73.6 +/- 13.8 to 82.2 +/- 15.2 ms; n = 14, p less than 0.01. The minimal effective plasma concentration was 347 +/- 147 ng/ml. The plasma concentration/dose ratio of children over 4 years of age was the same as in adults. It was significantly higher in babies and infants suggesting a progressive acquisition of the capacity to metabolise flecainide during the first year of life. In conclusion, flecainide acetate was easy to use with respect to administration and follow-up, and seems to be a drug of choice for the treatment of junctional tachycardia in children.

[Cardiac pacing in children with breath-holding spells]. / Stimulation cardiaque dans les spasmes du sanglot de l'enfant.

Breath-holding spells are common and usually benign. However, the authors chose to implant a pacemaker in children presenting with severe symptoms. Over the last 15 years, 11 children with severe breath-holding spells were paced. All had reflex spells with loss of consciousness, spontaneously or after minor trauma, and 6 had seizures. All had a normal ECG with marked bradycardic responses to ocular pressure. The 24 hour ECG showed pauses (12-25 s) in 4 patients, sudden bradycardia (< 30/min) in 3 patients, and sinus arrhythmia in the remaining 4 patients. Medical treatment has been unsuccessful. Pacemaker implantation was decided because of the severity and/or the frequency of the episodes in 10 children, and because of intolerable familial anxiety in the other one. Age at implantation ranged from 14 months to 5.5 years (mean: 16.5 +/- 20 months). The device was implanted by an epicardial (7) or from an endocardial (4) approach. All had a ventricular demand device, except for one who was paced from the atrium. The results were spectacular, with disappearance of spells and restoration of normal activities. Holter monitoring showed normal function of the pacemakers. Recurrences were observed in 3 patients, either due to loss of capture (2 cases) or to the need for explantation because of cutaneous erosion. Follow-up ranged from 10 months to 14 years (mean: 7.9 +/- 4.2 years); 2 patients were lost to follow-up; 4 patients totally recovered and only 5 are still vagotonic. Two pacemakers have been changed at 13 and 15 years respectively. The authors conclude that although psycho-social factors play a part in breath-holding spells, pacemaker implantation is very effective in suppressing symptoms in severely affected children.

[Angelman syndrome and severe vagal hypertonia. Three pediatric case reports]. / Syndrome d'Angelman et hypertonie vagale sévère. A propos de trois observations pédiatriques.

Angelman's syndrome is an association of severe mental retardation with absence of language, ataxia, convulsions and hyperactive, joyful behaviour with frequent bouts of laughing. Genetic diagnosis is possible in about 80% of cases. No cardiovascular abnormalities have been described in this syndrome to date. The authors report the cases of three children with Angelman's syndrome who presented with severe malaise due to increased vagal tone. The age of onset of symptoms was between 20 months and 8 years. One of the children had malaises triggered by bouts of laughing. The diagnosis was confirmed in all three cases by the results of Holter 24 hour ECG recording and oculo-cardiac reflex. The treatment chosen was Diphemanil (Prantal) in the two patients under 2 years of age (after failure of a trial of betablockers in one case) and Disopyramide for the oldest child with excellent results in all cases. However, one child died suddenly at the age of 6, two years after stopping diphemanil. Based on these observations, the authors suggest that all malaises in patients with Angelman's syndrome should be investigated by Holter ECG and oculo-cardiac reflex (or tilt test). In view of the potential gravity of the syncopal attacks, long-term medical treatment seems to be justified.

[Arrhythmia after atrial correction of transposition of the great vessels. Holter recording study of 123 surgically treated patients]. / Troubles du rythme après corrections atriales des transpositions des gros vaisseaux. Etude par enregistrement Holter de 123 opérés.

Sinus node dysfunction after intra-atrial repair of transposition of the great arteries by a Mustard or Senning procedure is well known. We undertook this study to evaluate the frequency, the nature, the severity and evolution of these dysrhythmias by performing Holter monitoring in 123 children followed up over 5 years; 302 Holter recordings were reviewed. The patients were divided into 3 groups of increasing severity: I = no sinus node dysfunction, II = moderate sinus node dysfunction, III = severe sinus node dysfunction with bradycardia of less than 30/min and/or pauses of over 2000 ms. The association of atrial hyperexcitability was classified in 3 subgroups: A = no extrasystoles, B = at least 4 extrasystoles per 24 hours, C = atrial tachycardia (focal tachycardia or flutter) after the first six postoperative months. There were only 15% of normal recordings (IA) and the majority of children (58%) were classified in the intermediary groups (IB, IIA and IIB). Sinus node dysfunction tended to become more severe with time in nearly 30% of the 69 cases followed up sequentially. The bradycardia tended to become more severe and associated with episodes of atrial tachycardia: the frequency of type B and C increased to 30% in Group I, to 68% in Group II and to 91% in Group III. The attacks were severe, especially in patients with a mediocre postoperative haemodynamic result. This explains the global mortality of 3%, the morbidity of 15% and the pacemaker implantation rate of 12%.(ABSTRACT TRUNCATED AT 250 WORDS)

[Medical treatment and long-term development of permanent reciprocal tachycardia in children. Apropos of 10 cases followed for 11 years]. / Traitement médical et évolution à long terme des tachycardies réciproques permanentes de l'enfant. A propos de 10 cas suivis durant 11 ans.

Incessant reciprocating tachycardia (IRT) was diagnosed in 10 children aged 0-11 years (mean 2.5 years), followed-up for an average of 11 years (range 4-22 years). 8 children were treated for an average period of 2.8 years (range 0.5-6 years) with the association of amiodarone and digitoxine. All children were treated initially or secondarily with verapamil and/or betablockers with digitoxine for an average of 4.6 years (range 1-9 years). The true frequency of IRT, its tolerance and the age at diagnosis did not indicate the probable required length of treatment with amiodarone, but only the initial response to this drug. Finally, 5 patients were cured and in sinus rhythm, and the other 5 were well controlled, having only occasional bursts of tachycardia. When we compared one group of 5 cases with clinical signs of cardiac failure and radiological cardiomegaly (CTR greater than 0.60) with a second group of 5 cases in which the arrhythmia was better tolerated, surprisingly, the frequency of intreated IRT was not t he factor which influenced its tolerance (198/min vs 194/min). On the other hand, the following differences were observed between the two groups: a younger age at diagnosis in the first group (5 months vs 4.6 years) responsible for the longer follow-up period (14.5 vs 7 years), earlier treatment period with amiodarone (3.6 years compared to 5.5 years) and a longer treatment period with this drug (3.5 vs 2 years). It was only at about the age of 7 that this treatment could be withdrawn or changed with half the children completely cured, and the other half only controlled.(ABSTRACT TRUNCATED AT 250 WORDS)

[Vagal hyperreactivity and sudden infant death. Study of 15 families]. / Hyperréactivité vagale et mort subite dans la fratrie. Etude des 15 familles.

Prone sleep position is obviously the main risk factor for sudden infant death. Other risk factors, such as vagal overactivity particularly in the familial form, are still discussed. We here report 15 families characterized by the coexistence of vagal overactivity and sudden infant death. At least, 1 child for each family had documented [Holter or occulo-cardiac reflex (OCR)] vagal overactivity. In 5 families 2 children were affected; in 2 families 3 children were affected and in 1 family 4 children were affected. Sudden death occurred in the elderly of the family in 8 cases, in the twin in 3 cases, in the 2nd in 3 cases and in the 5th child in 1 case. Within the 15 families, at least 1 parent had experienced vagally-induced fainting or syncope in 10 cases. Familial pattern of vagal overactivity is underlined. Possible links between vagal overactivity, risk factor for suddden death and sudden death are discussed. We suggest an Holter-ECG and OCR follow-up for sudden infant death siblings with history of familial vagal overactivity (3 examinations during the 1st year of life, at 1, 3 and 9 months).

[T wave abnormalities on Holter monitoring of congenital long QT syndrome: phenotypic marker of a mutation of LQT2 (HERG)]. / Anomalies de l'onde T au Holter dans le syndrome du QT long congénital: marqueur phénotypique d'une mutation dans LQT2 (HERG).

The two genes which code for the potassium channels, KCNQ1 and HERG, are responsible for the most common forms of the long QT syndrome, LQT1 and LQT2. Abnormalities of duration and morphology of the ventricular repolarisation are amongst the diagnostic criteria of this syndrome. The morphology of the T waves was studied by 24 hour Holter monitoring in 190 subjects with a long QT syndrome due to KCNQ1 (LQT1) [N = 133] or HERG (N = 57) and in 100 controls, and it was compared with the ECG T wave. The T wave was characterised according to 3 morphological features: grade 0 (G0) = normal, grade 1 (G&) = slight ST depression and grade 2 (G2) = presence of ST elevation of the descending phase of the T wave. The T wave morphology on Holter ECG was normal for most LQT1 and control subjects compared with LQT2 (92%, 96% and 19% respectively, p < 0.01). Grade 1 appearances were observed more often in LQT2 (18 vs 8% for LQT1 and 4% for controls, p < 0.01). Grade 2 appearances were only observed in the cases of LQT2 (63%). The predictive factors of G2 were young age and an anti-sense mutation of the transmembrane domaines of HERG. The authors conclude that Holter monitoring improves detection of T wave changes compared with the ECG. Grade 2 changes seem to be a phenotype marker for a HERG mutation, especially those situated in the transmembrane domaines.

[Congenital long QT syndrome. The value of genetics in prognostic evaluation]. / Syndrome du QT long congénital. Apport de la génétique dans l'évaluation pronostique.

The congenital long QT syndrome (QTL) is a heterogenic clinical and genetic entity characterised by prolongation of the QT interval which may be complicated by syncope and sudden death. Four genes have been identified for the cardiac potassium (KCNQ1, HERG and KCNE1) and sodium (SCN5A). The aim of this study was to assess the prognosis of the disease by the site of mutation identified on the morbid gene. Thirty-two genotyped families participated to this study. Each subject gave a clinical history, an ECG and a search for genetic mutation. Eighteen mutations in the transmembrane domains of KCNQ1 were identified in 25 families and 2 mutations in the C-terminal part were found in 4 families. The phenotype was less severe in C-terminal part mutations: less syncopes and sudden deaths (22 vs 55%, p < 0.001) and a shorter QTc (458 +/- 31 ms vs 479 +/- 31 ms, p = 0.0003). Three mutations were detected in the C-terminal part of HERG in 3 different families. Their phenotype was less severe with syncoped related to hypokalemia. The authors also report the case of a family in which two subjects who were the most severely affected had two mutations, one in HERG and the other in KCNQ1. This study confirms the value of a genetic research in assessing the severity of the congenital long QT syndrome.

[Anti-arrhythmia efficacy of propafenone in children. Apropos of 30 cases]. / Efficacité anti-arythmique de la propafénone chez l'enfant. A propos de 30 cas.

Thirty children aged from 3 months to 20 years were treated with propafenone 250 to 650 mg/m2 divided into 2 to 4 daily doses, for a mean period of 14 months (range: 4 days to 5 years); 8 had chronic atrial tachycardia, 9 had junctional arrhythmia and 13 had ventricular arrhythmia. There were 17 good results (suppression of the arrhythmia), 7 fair results (good clinical effect but partial persistence of the arrhythmia) and 6 failures, either because the drug proved ineffective (3 cases) or on account of side-effects (3 cases). In the treatment of chronic atrial tachycardia propafenone seemed to be more effective than amiodarone in 3 cases and as effective as that drug in 2 cases. In junctional arrhythmia propafenone was certainly effective but unpredictably so (3 good results, 2 fair results, 4 failures). Among ventricular arrhythmias, ventricular tachycardia in bursts was the one which benefited most regularly from treatment with propafenone: the results in 8 patients were better than those obtained with other antiarrhythmic agents (class I drugs, beta-blockers, calcium antagonists); only amiodarone proved superior to propafenone in this type of arrhythmia. Despite a 27% incidence of side-effects, propafenone was generally well tolerated by the children, with no significant gastrointestinal disorders. No depressive effect on the myocardium was noted in 6 children with moderate heart failure well controlled by digitalis and diuretics. However, since overdosage may cause severe disorders of conduction with widened ventriculogram, we recommend regular ECG monitoring during the first 3 days of treatment at least: although there is little slowing down of sinus rate (12%) and little modification of the slow phase under treatment, serious toxicity is possible. Thus, propafenone is a drug that should be handled with caution, but it constitutes a major addition to the range of antiarrhythmic agents which can be used in paediatrics.

[Sustained ventricular tachycardia in older children. Spontaneous regression in 3 cases]. / Tachycardie ventriculaire en salve soutenue du grand enfant. Guérison spontanée de 3 cas.

Extensively described since Gallvardin's reports, the electrical features of salves of ventricular tachycardia in an apparently healthy heart are now well known. The usual benign nature of this arrhythmia is acknowledged, seldom contradicted by isolated clinical cases. Although chronicity is the rule in young adults, there have been a few publications concerning the natural history of these tachycardias in the paediatric age group. The authors report three cases of episodic sustained ventricular tachycardia in older children, presenting at an average of 7 years of age (range 5 to 9 years) and followed up for an average of 7 years (range: 5.5 to 9 years). These three children were treated for an average of 4.5 years (range: 3 to 5.5 years). All treatment was finally withdrawn when stable permanent sinus rhythm without ventricular extrasystoles was restored and confirmed over an average period of 2 years (range 10 months to 3.5 years), an average of 4 (range 3 to 7) successive normal Holter recordings at several months' interval. The outcome in children to spontaneous regression after several years would seem to make radiofrequency ablation more dangerous than useful given the benign nature of the arrhythmia and its good response to pharmacological intervention.

[The autonomic nervous system in sudden infant death syndrome. Analysis of heart rate and sinusal variability on Holter monitoring of infants who died]. / Le système nerveux autonome dans le syndrome de la mort subite du nourrisson. Analyse du rythme cardiaque et de la variabilité sinusale sur les enregistrements Holter d'enfants décédés du syndrome.

To evidence abnormality of cardiac control by the autonomic nervous system in the sudden infant death syndrome (SIDS) we retrospectively analysed the Holter recordings and cardiopneumograms of 19 infants (11 boys, 8 girls) of mean +/- SD age 2.3 +/- 1.5 months who had subsequently died of SIDS. Two infants were regarded as normal and the reference diagnoses in the remaining 17 infants were: apparent life threatening event (8), SIDS siblings (8) and prematurity (1). At the time of death the age was 4.2 +/- 2 months. Each of these infants was matched with three control infants in term of postnatal age, gestational age and reference diagnosis, but without SIDS at follow-up of at least one year. Nine hours of Holter recordings (9 p.m. to 6 a.m.) were analysed in term of mean heart rate and sinus oscillations waves. To differentiate between short oscillations of 4 to 6 RR, which are induced by respiration and reflect vagal activity, and long oscillations of 20 to 32 RR, which reflect both neurogenic sympathetic and vagal activity, we used a new method which measures the number and the amplitude in milliseconds of each type of oscillations. The results are expressed as the logarithm of the product of these two variables. Heart rate, correlated to age in both groups, is higher in the deceased infants group (141 +/- 14 mn and 135 +/- 15; p less than 0.05: analysis of covariance with age as an independent variable). Short oscillations, also correlated to age, are lower in the deceased infants group (3.35 +/- 0.59 and 3.65 +/- 0.61; p less than 0.05: analysis of covariance with age).(ABSTRACT TRUNCATED AT 250 WORDS)

[Andersen syndrome, ventricular arrhythmias and channelopathy (a case report)]. / Maladie d'Andersen, channelopathies et arythmies ventriculaires (à propos d'un cas).

INTRODUCTION: Recent advances in molecular genetic research have provided new insights into severe ventricular arrhythmias related to channelopathies. CASE REPORT: A case of Andersen's syndrome followed during fourteen years is reported. This rare familial periodic paralysis is characterized by its association with dysmorphic features (micrognatia) and ventricular arrhythmias. COMMENTS: Andersen's syndrome has been attributed to a mutation in the KCNJ2 gene which is involved not only in stabilizing cardiac rhythm, but also in modulating the excitability of skeletal muscle and in morphogenesis. This disease must be distinguished from hyperkalemic periodic paralysis due to a mutation in the skeletal muscle sodium channel gene (SCN4A) and from hypokalemic periodic paralysis related to dihydropyridine receptor mutation (CACNL1A3). Furthermore, it may not be confused with others rhythmic channelopathies (long QT syndromes, catecholaminergic polymorphic ventricular tachycardia and Brugada's syndrome).

[Long term course of catecholaminergic polymorphic ventricular tachycardia in children. Apropos of 20 cases with an 8 year-follow-up]. / Devenir à long terme des tachycardies ventriculaires polymorphes catécholergiques de l'enfant. A propos de 20 cas suivis pendant 8 ans.

BACKGROUND: Primary ventricular arrhythmias are rarely seen in children. Some of them have a poor prognosis; they should be diagnosed because adequate treatment can prevent sudden death. POPULATION AND METHODS: Twenty children (11 male, nine female), aged 3 to 16 years (mean: 7.7 +/- 4), with apparently normal hearts and normal QTc intervals were referred for stress or emotion-induced syncope. Primary ventricular arrhythmia, consisting of isolated polymorphic ventricular extrasystoles followed by salvos eventually degenerating into ventricular fibrillation, was reproducibly induced by physical exertion. The syncopal events and "torsades de pointe" disappeared with beta-blocking therapy. A total of four syncopal events and two sudden deaths occurred during a mean follow-up of 8 years, probably due to discontinuation of treatment. DISCUSSION: Fifty-four-cases of stress-induced severe polymorphous ventricular arrhythmia have been reported in the literature. There were four sudden deaths in 37 patients on beta-blocking therapy, and ten sudden deaths in 21 untreated patients. CONCLUSION: Clinically close to the congenital long QT syndrome, this primary ventricular arrhythmia must be looked for in cases of stress or emotion-induced syncope. The diagnosis relies on Holter monitoring and a stress test. Life-long beta blocker therapy is required.

[Torsade de pointes syndromes. Variations and limits]. / Les syndromes de torsades de pointes. Variétés et limites.

Advances in cardiac rhythm studies have led to more precise definitions of wave burst arrhythmias since they were first described by Dessertenne. This progress has also broadened the scope of these arrhythmias and the initially defined limits no longer apply. Prolonged Q-T syndromes, whether inherited or acquired, remain the standard, characterized by the ECG so typical of tachycardiac rhythms with long coupling of the initial extrasystole. In the congenital forms, neurogenic, sympathetic stimulation plays a triggering role, whereas sympathetic hypertonia of humoral origin protects acquired forms. Catecholaminergic ventricular tachycardia is clearly related to congenital Q-T syndrome and involves the same treatment, but tends to show idiosyncrasy to quinidine compounds, in common with acquired forms of Q-T syndrome. Short-coupling wave burst arrhythmias are congenital and in principle idiopathic. They have triggering factors in common with acquired prolonged Q-T syndromes, but their interactions with the autonomic nervous system are more complex; the vagus and sympathetic nerves are equally implicated and these interactions are curiously sensitive to calcium antagonists. These four related syndromes form an "ill-defined group" the limits of which will become clearer as more knowledge is acquired regarding the substrate and the interactions with the autonomic nervous system.

[Effect of atropine therapy on sudden infant death. A multicenter survey of 7851 children at risk]. / Effet du traitement atropinique sur la mort subite du nourrisson. Enquête multicentrique réunissant 7,851 enfants à risque.

The results of a multicentre inquiry started in 1988 in reference centres of sudden infant death are presented. This study concerns the sudden and unexplained mortality of infants under 1 year of age who were treated with atropinics for an alleged risk of sudden death. The 7,851 infants involved were divided into 2,605 siblings, 1,067 premature babies and 4,179 infants who experienced malaises. Only one of the 2,034 infants treated with atropinics (385 siblings, 435 prematures, 1,214 with malaise) died, as opposed to 27 deaths among the 5,817 infants who where not treated (10 deaths among 2,220 siblings, 6 among 632 premature and 11 among 2,965 infants with malaise); P = 0.005. These results are encouraging, but they suffer from the limitations and biases inherent in all large inquiries. They certainly do not allow us to conclude without reservation that vagal hyperreflectivity is the mechanism responsible for sudden infant death and that atropinics must be systematically given to all infants at risk. Wide and randomized prospective studies are highly desirable in this particular field.