Bidirectional Ventricular Tachycardia and Prominent U Waves: Look at Fingers and Muscles and Use Flecainide.

We present a case of bidirectional ventricular tachycardia in a 15-year-old boy asymptomatic for arrhythmias, whose major complaint was muscle weakness. At our first evaluation he was receiving sotalol for his ventricular arrhythmias. In addition to bidirectional tachycardia, electrocardiogram during sinus rhythm showed prominent U waves and prolonged QT-U interval. These electrocardiographic signs, along with the evidence of clinodactyly and mild hypertelorism, led us to the diagnosis of Andersen-Tawil syndrome, confirmed by genetic analysis that revealed a "de novo" missense mutation of KCNJ2 gene. Monotherapy with flecainide was rapidly effective and almost eliminated ventricular arrhythmias. After a 4-year follow-up there were no adverse events, flecainide has been well tolerated without significant modification of the QRS or repolarization, and ventricular arrhythmias have not been relapsed to date. The case highlights the importance of a correct clinical diagnosis, which is crucial for the optimal selection of the most appropriate drug therapy, which is expected not to be harmful, before being beneficial.

Electrophysiological guided accessory-pathway ablation strategy in children with asymptomatic WPW: it may not be enough to prevent sudden cardiac death.

BACKGROUND: Sudden cardiac death (SCD) may rarely occur among asymptomatic patients with Wolff-Parkinson-White (WPW) pattern. Risk stratification is based on electrophysiological study (EPS). We aimed to evaluate long-term efficacy of such a strategy in preventing SCD. METHODS: Retrospective analysis of asymptomatic children with WPW who underwent EPS using isoproterenol. Patients considered at risk had inducible sustained atrial fibrillation or atrioventricular reentry tachycardia (AVRT) associated with the following: (1) accessory pathway (AP) effective refractory period or (2) 1:1 shortest cycle length along the AP or (3) shortest pre-excited R-R interval during AF ≤ 250 ms. RESULTS: Fifty-one consecutive cases (7-18 years, 12 ± 3) were identified, 40 (78%) with right and 11 (22%) with left AP. Twenty-eight (55%) were classified as high risk (HI) and 23 (45%) as low risk (LO), with no significant differences in demographic characteristics and AP locations. Ablation was performed in 20/28 HI and 11/23 LO patients (p 0.08), with no significant differences in acute success (20/20 versus 10/11, p 0.17) or recurrence (1/20 versus 2/10, p 0.15). Follow-up (46 ± 27 months): ablated patients remained asymptomatic; among the 23 non-ablated, 18 (78%) remained asymptomatic, 5 (22%) were successfully ablated, and 5 (22%) presented events (4 AVRT, 1 SCD). Arrhythmic events did not differ significantly between non-ablated HR and LR (2/8 versus 3/15, p 0.29) and the SCD was in the LO group. CONCLUSIONS: More than 50% asymptomatic WPW children present high-risk AP properties. EPS-based risk stratification using isoproterenol was not able to identify increased risk of future events or SCD.

Anomalous aortic origin of the pulmonary arteries: Case series and literature review.

Anomalous origin of the pulmonary arteries from the ascending aorta is a rare, but severe clinical entity necessitating a scrupulous evaluation. Either the right or the left pulmonary arteries can arise directly from the ascending aorta while the other pulmonary artery retains its origin from the right ventricular outflow tract. Such a finding can be isolated or can coexist with several congenital heart lesions. Direct intrapericardial aortic origin, however, must be distinguished with origin through a persistently patent arterial duct. In the current era, clinical manifestations usually become evident in the newborn rather than during infancy, as used to be the case. They include respiratory distress or congestive heart failure due to increased pulmonary flow and poor feeding. The rate of survival has now increased due to early diagnosis and prompt surgical repair, should now be expected to be at least 95%. We have treated four neonates with this lesion over the past 7 years, all of whom survived surgical repair. Right ventricular systolic pressure was significantly decreased at follow-up. Our choice of treatment was to translocate the anomalous pulmonary artery in end-to-side fashion to the pulmonary trunk. Our aim in this report is to update an Italian experience in the diagnosis and treatment of anomalous direct origin of one pulmonary artery from the aorta, adding considerations on the lessons learned from our most recent review of the salient literature.

Erythrocytosis and severe asphyxia: two different causes of neonatal myocardial infarction.

Neonatal acute myocardial infarction is a rare event that carries a high mortality rate. We describe the cases of two newborns who survived acute myocardial infarction and discuss the management. The first neonate was born with severe asphyxia and left ventricular myocardial infarction with ventricular tachycardia. In this patient, systemic flow was maintained by right-to-left shunting through the patent ductus arteriosus. The second neonate presented with a haematocrit of 80% and an inferolateral myocardial infarction. Intensive treatment of low cardiac output syndrome led to survival of both high-risk neonates. In the follow-up, at 48 and 4 months, respectively, ventricular function recovered in both patients.

Clinical and electrophysiological characteristics, and relatively benign outcome, of typical atrioventricular nodal reentrant tachycardia in children and adolescents.

BACKGROUND: Atrioventricular nodal re-entrant tachycardia is an uncommon arrhythmia in children. The natural history of this disturbance is poorly known in young patients. METHODS: We analyzed the clinical and electrophysiological features, and the final outcome, in 19 children affected by typical atrioventricular nodal re-entrant tachycardia diagnosed by a transoesophageal electrophysiological study. RESULTS: Of the cohort, 12 patients were female and 7 male, with a mean age of 11 years. Dual atrioventricular nodal physiology was demonstrated in 14 children (73%). The mean length of the tachycardia cycle was 297 milliseconds, with periods of 2 to 1 atrioventricular block during tachycardia noted in 5 children (26%). The mean cycle length was significantly shorter in the children who presented episodes of 2 to 1 atrioventricular block than in those who did not. After diagnosis, 12 children were not treated, 6 were treated with medical therapy, and 1 was submitted to radiofrequency transcatheter ablation. During a mean follow-up period of 41 months, 2 children with rare, but sustained, episodes of tachycardia that initially had not been treated were submitted to radiofrequency transcatheter ablation. Among children treated pharmacologically, 1 teenager was submitted to radiofrequency transcatheter ablation on the basis of parental choice, 3 children have discontinued medical therapy recording only sporadic episodes of tachycardia, and 2 children are still treated with antiarrhythmic drugs. At the last follow-up visit, 13 children (68%) were without any treatment, 4 had been successfully ablated, and 2 were still on medical treatment. CONCLUSIONS: Our data indicates a relatively benign outcome in this group of children and adolescents with atrioventricular nodal re-entrant tachycardia.

Congenital quadricuspid aortic valve in children.

Quadricuspid aortic valves are rare congenital anomalies, usually diagnosed in adult patients affected by severe aortic regurgitation. We have now encountered three such valves in children undergoing transthoracic echocardiography. All children were asymptomatic. The first child possessed a valve with two larger leaflets, and smaller leaflets of equal size. In the second child, 3 leaflets were of equal size, with 1 small accessory leaflet. The third child had a valve with four leaflets of approximately equal size. In one child, the aortic valve was functioning normally, and came to attention because of mitral valvar prolapse causing mild regurgitation. In the remaining two children, central mild aortic regurgitation was detected using colour flow analysis, and associated dilation of the aortic root was revealed by measurements of the cross-sectional images.

Efficacy of closed-loop stimulation with epicardial leads in an infant with congenital atrioventricular block.

We present the case of an infant with a congenital atrioventricular block and sinus node dysfunction that was implanted with a pacemaker with physiological closed-loop stimulation (DDD-CLS) pacing mode with two epicardial leads. We have observed the response of DDD-CLS system with respect to conventional rate responsive accelerometer-based mode (DDDR): the atrial pacing percentage and the 24 h rate trend showed higher values during DDD-CLS compared with DDDR. In this patient, rate responsive feature seems preserved in DDD-CLS also using epicardial leads.

The total absence of atrial automaticity in a child with sinus node dysfunction.

BACKGROUND: A routine sports evaluation identified constant alternation between a junctional and idioventricular rhythm in a 9-year-old child. During exercise testing, electrography demonstrated that the child was in junctional rhythm without any apparent P waves, and had a reduced increase in heart rate. Endocardial atrial pacing captured the atrium and demonstrated that atrioventricular conduction was normal, but the recovery time of the ectopic rhythm was very long. Three-dimensional electrophysiological mapping revealed 1:1 retrograde homogeneous conduction through the right atrium. INVESTIGATIONS: Electrocardiography, Holter monitoring, echocardiography, exercise stress testing, atrial pacing, three-dimensional electroanatomical mapping of the right atrium and genetic testing. DIAGNOSIS: Sinus node dysfunction. MANAGEMENT: Pacemaker implantation was postponed until a later stage in the patient's development.

Permanent cardiac pacing for severe pallid breath-holding spells.

We report the case of an infant affected by frequent episodes of loss of consciousness with the clinical features of pallid breath-holding attacks. Prolonged asystole, up to 26 seconds, was demonstrated by Holter monitoring. The patient was treated with permanent pacemaker implantation, followed by complete symptom resolution during a 26-month follow-up.

Exclusion of fluoroscopy during ablation treatment of right accessory pathway in children.

INTRODUCTION: The field of pediatric electrophysiology poses many challenges to electrophysiologists. In particular there are two major concerns: (1) to reduce the amount of fluoroscopy exposure to patients and medical staff in the catheterization laboratory and (2) to minimize the number of vascular accesses. Prolonged fluoroscopy times are associated with radiofrequency (RF) ablation of right accessory pathways (APs), particularly the right free-wall AP. The aim of this study was to eliminate the use of fluoroscopy during treatment of right-sided APs in children while using a single-catheter approach. METHODS AND RESULTS: We studied 21 consecutive pediatric patients (mean age 11.3 +/- 3.2 years) with Wolff-Parkinson-White syndrome due to a right AP. To limit fluoroscopy use, we used a three-dimensional navigation system that facilitated reconstruction of a three-dimensional electroanatomic activation map along the tricuspid annulus either on the atrial side during orthodromic AV reciprocating tachycardia or along the ventricular side during anterograde preexcitation. RF application was successful and without complications in 20 patients (success rate 95%); moreover, 19 of the 21 patients underwent a single-catheter procedure. The remaining two patients required an additional quadripolar catheter for atrial stimulation. A mean of 2 +/- 1 RF applications were used during the whole study. CONCLUSION: Our study demonstrates that ablation of right APs in children can be performed without fluoroscopy using a single catheter with minimal amounts of RF applications. Our new technique is associated with high success rates.

Mustard procedure in atrial situs inversus: three-dimensional ablation of intra-atrial reentry tachycardia on a surgically created inversus cavo-tricuspid isthmus.

It has been demonstrated that the Biosense Carto system can improve the success rate of ablation in case of an intra-atrial reentry tachycardia in patients submitted to the Mustard repair. This system was used to map an intra-atrial reentry tachycardia in a young patient who had been submitted to the Mustard procedure for atrial situs inversus. A line of block was created connecting the right sided tricuspid valve to the left sided inferior vena cava. This terminated the arrhythmia and prevented its re-initiation. This case confirmed the notion that the cavo-tricuspid isthmus is often critical to the maintenance of an intra-atrial reentry tachycardia after the Mustard procedure even if its location is in the inversus side.