[Acute poststreptoccocal chorea: an atypical postoperative reaction following cardiac surgery for mitral valvulopathy]. / Chorée aiguë post-streptococcique : une étrange réaction après chirurgie d'une insuffisance mitrale rhumatismale.

We report on a 12-year-old patient from Congo who presented acute chorea following cardiac surgery for poststreptococcal mitral valvulopathy. She showed severe and asymmetrical chorea, associated with motor impersistence and agitation. Biological investigations disclosed inflammatory signs and brain MRI was normal. Due to the negative results of the biological and morphological investigations, the diagnosis of Sydenham chorea was suspected. High doses of oral steroids resulted in a dramatic improvement of the chorea as well as the behavior disturbance within 1 month. Sydenham chorea is not an unusual complication of rheumatic fever. Usually, patients develop chorea a few weeks after beta-hemolytic streptococcal pharyngitis. Details on its pathophysiology remain to be determined. Our case highlights its possible onset in the postoperative period if alternative etiologies of infantile chorea have been excluded.

[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.

Permanent junctional reciprocating tachycardia in children: a multicentre study on clinical profile and outcome.

OBJECTIVES: To investigate the clinical profile, natural history, and optimal management of persistent or permanent junctional reciprocating tachycardia (PJRT) in children. METHODS AND RESULTS: 85 patients meeting the ECG criteria for PJRT were enrolled in a retrospective multicentre study. Age at diagnosis varied from birth to 20 years (median 3 months). Follow up ranged from 0.1 to 26.0 (median 8.2) years. At the time of referral, 24 of 85 patients (28%) had congestive heart failure that was resolved with medical treatment in all patients. Eighty three patients received drug treatment initially. Amiodarone and verapamil were the most effective with a success rate of 84-94% alone or in association with digoxin. Radiofrequency ablation of the accessory pathway was performed in 18 patients. There was a trend for a relation between age at ablation and the result of the procedure, failures being more common in younger patients (three of six procedures in younger and 15 of 18 in older children were successful; p = 0.14). Two patients with persistent left ventricular dysfunction on echocardiography but with no symptoms of congestive heart failure died suddenly one month and three years after diagnosis. PJRT resolved spontaneously in 19 patients (22%). Age at diagnosis of PJRT was not a predictor of spontaneous resolution. CONCLUSIONS: PJRT is a potentially lethal arrhythmia in children with tachycardia induced cardiomyopathy. Spontaneous resolution of tachycardia is not uncommon. Antiarrhythmic treatment is often effective. Radiofrequency ablation should be performed in older children or when rate is not controlled, especially in patients with persistent left ventricular dysfunction.

[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.

Low incidence of cardiac events with beta-blocking therapy in children with long QT syndrome.

AIMS: To evaluate the effect of beta-blockers in children with long QT syndrome (LQTS) we reviewed the outcome of 122 patients (pts). METHODS: LQTS was diagnosed in 24 neonates and in 98 pts aged 0.5-15 years. Diagnosis was made because of syncope in 51 pts, bradycardia in 10 neonates and family history in 61 pts. The longest QTc ranged from 400 to 700 ms. Thirteen pts had 2:1 atrioventricular block and/or ventricular arrhythmias. Screening for mutations was performed in 118 pts. All children were treated with beta-blockers, annually checked by exercise testing and/or 24 h ECG monitoring. RESULTS: Four pts died. Survivors were followed-up for 1-18 years (7.5 +/- 5.3 years). Five neonates and 3 older pts received a prophylactic pacemaker (1 death) so that only 111/122 pts survived and were followed-up with beta-blockers alone. None of them died and five experienced a non-fatal cardiac event. There was no cardiac event among pts who were diagnosed because of familial history and among symptomatic KCNQ1 pts who were effectively treated with beta-blockers. CONCLUSION: The outcome of children with LQTS under effective beta-blockers is favourable. Persisting arrhythmia or symptoms despite beta-blockers should aim at identifying other genotypes than KCNQ1.

[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.

[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.

[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).

[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).

[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.

Paroxysmal vagal overactivity, apparent life-threatening event and sudden infant death.

The possibility of reversible cardiac asystoly due to paroxysmal vagal overactivity (VO) has been well studied, first in adults, then in children, and finally in breath-holding spells. Few studies deal with infants and the incidence of VO among preterm, apparent life-threatening event (ALTE) and sudden infant death syndrome (SIDS). In this review, we summarize data acquired during the past 20 years leading to the diagnosis of VO in infants. We describe the clinical aspects of VO in infants and young children such as Holter-ECG and oculocardiac reflex criteria. The familial aspect of VO and its possible link with SIDS (a new risk factor?) are discussed. Finally, whether or not to treat infants with symptomatic VO is discussed.

[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.

[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.

[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.