[Neonatal atrial tachycardia: suggestive clinical sign of Costello syndrome]. / La tachycardie atriale néonatale : association non fortuite avec le syndrome de Costello. À propos de 2 cas.

Costello syndrome is a rare association of symptoms caused by de novo germline mutations of the HRAS oncogene interfering in the RAS/mitogen-activated protein kinase (MAPK) signal transduction pathway. Mutations in this pathway are also responsible for Noonan syndrome and the related cardiofaciocutaneous syndrome (CFC) as well as LEOPARD syndrome. The 4 syndromes share phenotypic resemblances concerning patients' morphology but also regarding associated cardiac disease, namely hypertrophic cardiomyopathy, pulmonary stenosis, and atrial septal defect. The electrocardiogram often shows an upper deviation of the QRS axis. Arrhythmias are rare but, if present, are particularly typical of CS. We describe herein two newborn infants with Costello syndrome revealed by atrial tachycardia associated with characteristic morphological and cardiac features of syndromes related to mutations in the RAS/MAPK pathway.

KATP channel mutation confers risk for vein of Marshall adrenergic atrial fibrillation.

BACKGROUND: A 53-year-old female presented with a 10-year history of paroxysmal atrial fibrillation (AF), precipitated by activity and refractory to medical therapy. In the absence of traditional risk factors for disease, a genetic defect in electrical homeostasis underlying stress-induced AF was explored. INVESTIGATIONS: Echocardiography, cardiac perfusion stress imaging, invasive electrophysiology with isoproterenol provocation, genomic DNA sequencing of K(ATP) channel genes, exclusion of mutation in 2,000 individuals free of AF, reconstitution of channel defect with molecular phenotyping, and verification of pathogenic link in targeted knockout. DIAGNOSIS: K(ATP) channelopathy caused by missense mutation (Thr1547Ile) of the ABCC9 gene conferring predisposition to adrenergic AF originating from the vein of Marshall. MANAGEMENT: Disruption of arrhythmogenic gene-environment substrate at the vein of Marshall by radiofrequency ablation.

Successful implantation of a cardioverter defibrillator in an infant.

We report the successful implantation of a cardioverter defibrillator (ICD) in a 12-month-old infant. A single-lead ICD using an epicardial patch and a cathodal pulse-generator titanium shell electrode was very useful for implantation in this infant.

Paroxysmal supraventricular tachycardia in identical twins with the same left lateral accessory pathways and innocent dual atrioventricular pathways.

We report on 16-year-old, female identical twins who both have atrioventricular reentrant tachycardia caused by the same left lateral atrioventricular accessory pathway. The Kent pathway in twin A was a unidirectional retrograde accessory pathway. A manifest Kent pathway was demonstrated in twin B. Both pathways were successfully ablated by radiofrequency (RF) energy and without recurrence. In addition, innocent dual AV nodal pathways were shown in both patients. These findings suggest that genetic factors may play a role in the pathogenesis of the formation of accessory atrioventricular pathways and dual AV nodal pathways.

Lymphedema combined with brachydactyly and tachycardia.

Hereditary lymphedema can appear at birth or later up to adulthood. It may be seen in connection with diverse symptoms forming various syndromes. The authors report a family with hereditary lymphedema, brachydactyly, syndactyly and tachycardia. Lymphedema and tachycardia could appear together by chance. However this combination could also be a syndrome.

Radiofrequency catheter ablation in familial paroxysmal supraventricular tachycardia due to accessory atrioventricular pathways.

Radiofrequency catheter ablation (RF-CA) has been widely used to cure paroxysmal supraventricular tachycardia (PSVT). However, its use has never been reported in familial PSVT caused by an accessory atrioventricular pathway (AP), which is known as one of the typical familial cardiovascular diseases. Two cases of using RF-CA for familial PSVT due to APs are presented, in a brother and sister, supporting a potential genetic role in the developmental failure to lose the atrioventricular connection during fetal life. The sister, a 24-year-old woman, had intermittent episodes of palpitation accompanied by chest pain for 2 years. An electrophysiologic study (EPS) confirmed her clinical tachycardia was atrioventricular reentrant tachycardia (AVRT) due to a left lateral concealed AP, which was subsequently successfully ablated with RF-CA. The brother, a 22-year-old man, had a 5-year history of paroxysmal palpitation. A resting electrocardiogram showed a right bundle branch block and left axis deviation with a delta wave. During his EPS, AVRT was reproducibly induced and a manifest AP was localized and then ablated at the left posteroseptal site, resulting in disappearance of the delta wave. PSVT, however, recurred 1 month later and during a repeat EPS the tachycardia was proved to be AVRT due to a right anterior concealed AP. The right anterior AP was successfully ablated with RF-CA. Both patients remained asymptomatic for more than 3 years following the successful ablation procedures.

[Differences in the symptomatology of paroxysmal supraventricular tachycardias in relation to the different sites of localization of the arrhythmic reentry circuit. Clinical picture, semiologic and genetic aspects]. / Diversità di sintomatologia nelle tachicardie parossistiche sopraventricolari (TPSR) correlata alla differente localizzazione del circuito aritmico di rientro. Analisi del quadro clinico e considerazioni semeiogenetiche.

Transesophageal, electrophysiologic studies were conducted in 47 patients, with clinical and ECGgraphic diagnosis of paroxysmal reciprocating supraventricular tachycardia. After admission to hospital, the patients were enrolled in the study in accordance with the criterion concerning the exclusion of patients with signs and symptoms of severe heart pump failure (ie, NYHA III and IV class were excluded). The transesophageal study was performed during paroxysmal tachycardia in each patient to measure the V-A interval and to localize the site of reentry. Thereby, the patients could be grouped into 2 subsets, ie those with A-V nodal reentrant tachycardia (no. 30 patients) and those with accessory pathway reentrant tachycardia (no. 17 patients). Moreover, the prevalence in both subsets was evaluated in the following signs and symptoms: palpitations, dyspnoea, chest pain, pulsations in the neck, significant increase in urinary output, hypotension, dizziness, near-syncope, syncope, shock, focal brain injury. From the data analysis, significantly greater prevalence of palpitations in the neck resulted in the subset of patients with reentry confined to the A-V node (no. 20 cases) compared with those suffering from reentry via accessory pathway (no. 4 cases). Moreover the arterial pressure, in A-V nodal reentrant tachycardia, showed the lowest values and the best decreases, together with the finding of a more rapid trend to decline in comparison with the accessory pathway subset. On the other hand, no significant differences could be seen about the remaining symptoms. In an attempt to provide the reliable explanation for the differences found between the 2 subsets of study, concerning both the unpleasant pulsations in the neck and the pressure decrease, we postulated a remarkable role for the length of arrhythmic circle movement. The smaller dimensions of circuit limbs, in A-V nodal reentrant tachycardia, are likely to be the principle cause of the different clinical features of 2 types of reentry. We speculate actually that in susceptible patients the critical event is most likely to be A-V functional dissociation due to early and unphysiologic activation of atria by stimulus rapidly reentrant from the bottom portion of the AV node: the simultaneous occurrence, frequent in A-V node reentry, of both, atrial and ventricular mechanical activation, would result, however, in impairment of atrial haemodynamics due to development of cannon A waves, able either to activate a vasodepressor reflex from the atria or to stimulate instantaneous release of atrial natriuretic factor in the circulation. Further studies, however, are necessary to be performed on large cases-records, to confirm our hypothesis.(ABSTRACT TRUNCATED AT 400 WORDS)

[Apropos of a case of intra-uterine supraventricular tachycardia]. / A proposito di un caso di tachicardia sopraventricolare intrauterina.

A case of intrauterine paroxysmal supraventricular tachycardia (PSVT)--without heart malformations and fetal cardiac failure at the echographic assessment--is reported. After birth, the EKG of the newborn documented recurrent accesses of reentrant PSVT, likely related to the presence of a concealed Kent's bundle in the reentry circuit. Mother and grand-father of the newborn were affected by Lown-Ganong-Levine syndrome. The familial occurrence of pre-excitation syndromes--with different by-passes--and the possibility of autosomal inheritance are discussed. The importance of early identification of fetal cardiac dysrythmias and/or failure by monitoring pregnancies with familial history of PSVT is emphasized. Pharmacological approaches of fetal supraventricular tachycardia, as reported by several Authors in the literature, are presented.

[Paroxysmal AV tachycardia in triplets]. / Paroxysmale AV-Tachykardie bei Drillingen.

It is reported on triplet sisters with paroxysmal tachycardias. Two of them were enzygotic. For the two an AV-node longitudinal dissociation could be proved as cause of the tachycardia. This observation is regarded as proof for the existence of congenital anomalies of the AV-node as a possible cause of its longitudinal dissociation.

Identical twins with differing forms of ventricular pre-excitation.

Identical 10-year-old twins, both with electrocardiograms showing a short PR interval and a normal QRS complex but with dramatically different electrophysiological characteristics, are described. One twin experienced episodes of rapid palpitation and on one occasion was resuscitated from ventricular fibrillation. An intracardiac electrophysiological study confirmed the presence of an atrioventricular nodal bypass tract and in addition revealed the presence of an accessory atrioventricular pathway, thus demonstrating that the patient had both the Lown-Ganong-Levine and Wolff-Parkinson-White syndromes. Re-entry tachycardia and atrial fibrillation, with a very rapid ventricular rate, were precipitated. After treatment with amiodarone, the patient became asymptomatic and a repeat study showed that the features of the atrioventricular nodal bypass tract were no longer present and though re-entry tachycardias using the accessory atrioventricular pathway could still be induced, their rates were slower than before treatment. The other twin, in spite of an identical surface electrocardiogram, was asmymptomatic. An electrophysiological study showed the features of an atrioventricular nodal bypass tract but there was no evidence of additional atrioventricular accessory connections and a tachycardia could not be induced.

Familial atrial tachyarrhythmia with short PR interval.

A family had an unusual and perhaps unique familial dysrhythmia. The proband had a short PR interval with normal QRS and chronic recurrent paroxysmal atrial tachycardia (Lown-Ganong-Levine syndrome). The arrhythmia produced left ventricular dysfunction. Both paroxysmal atrial tachycardia (PAT) and left ventricular dysfunction were reversed with administration of digoxin and propranolol hydrochloride. Three family members had paroxysmal or chronic atrial fibrillation, first diagnosed at a relatively young age (23 years, 38 years, and early 40s, respectively). Five additional family members had short PR intervals with normal QRS, and eight other family members had borderline short PR intervals. The mode of inheritance appeared to be autosomal dominant with varying expressivity. We have described a familial syndrome characterized by PAT or atrial fibrillation in its advanced form with short PR interval as a possible identifying trait. The future course of members with isolated short PR is unknown.

[Pre-excitation syndrome in monozygotic twins]. / Sindrome de pre-excitación en gemelos univitelinos

A family group of seven members is presented, two of which have pre-excitation syndrome. These subjects are identical twin brothers. One of them has the W-P-W syndrome tipe B, and the other has L-G-L syndrome. The latter had an associated atrial-septal defect, and the other twin had no associated cardiovascular lesions. Both underwent electrocardiographic and vectorcardiographic studies, as well as His bundle electrograms. In the case with W-P-W, the diagnosis was made by electrocardiography, and was confirmed by vertocardiography. The His bundle electrogram showed the habitual findings in this type of pre-excitation. The His bundle potential was preceded by the beginning of the delta wave. The patient with W-P-W had episodes of supraventricular paroxysmal tachycardia, some of these with antegrade conduction through the normal pathway, and others with conduction through the anomalous pathway. The other had a L-G-L syndrome, demonstrated by electrocardiography and vectorcardiography. During the register of the His bundle electrogram, he did not present pre-excitation, the tracings in basal conditions as well as during atrial stimulation were normal. The conclusion is that many factors exist which back up the hypothesis that the pre-excitation syndromes occur because of anomalous pathways, and that this type of alteration might have a sex linked genetic basis. This presumption appears to be confirmed by the presence of pre-excitation in identical twin brothers. Other possibilities are also discussed.