Outcomes of junctional ectopic tachycardia ablation in adult population-a multicenter experience.

PURPOSE: Idiopathic junctional ectopic tachycardia (JET) is typically refractory to antiarrhythmic agents. Catheter ablation for JET is feasible but is associated with high risk of unintended atrioventricular (AV) block. There is limited data on the appropriate procedural technique and clinical outcomes with catheter ablation for idiopathic JET in adults. METHODS: This is a multicenter, retrospective study of all adult patients (age ≥ 18 years) who underwent catheter ablation for idiopathic JET. Patient, procedural characteristics, and long-term outcomes were evaluated. RESULTS: Fifteen patients [radiofrequency ablation (RF) = 14 and cryoablation = 1) were treated with catheter ablation. The median age was 58 years with 67% males. All patients underwent mapping of the right atrium and the aortic cusps prior to energy delivery. The location of earliest activation in relation to the atrioventricular (AV) node was postero-superior in 73% (11/15), posterior in 13% (2/15), and superior in 13% (2/15) respectively. Acute success was 100%. Arrhythmia recurrence occurred in 53% (8/15) all of whom underwent a repeat ablation. High-grade AV block requiring permanent pacemaker occurred in 20% (3/15). At 12-month follow-up in the redo-ablation group, 37.5% (3/8) had recurrence of the arrhythmia two of which underwent a third ablation procedure. CONCLUSION: Catheter ablation of idiopathic JET in adults is associated with a high rate of recurrence requiring multiple procedures and high risk of AV block requiring a permanent pacemaker. Mapping and ablation of the non-coronary cusp can be considered as the arrhythmia was controlled in 3 patients with no inadvertent AV block.

Pulmonary arterial hypertension associated with chronic active Epstein-Barr virus infection.

Chronic active Epstein-Barr virus (EBV) infection (CAEBV), characterized by persistent infectious mononucleosis-like symptoms, can lead to cardiovascular complications including coronary artery aneurysm or myocarditis. Here, we present the case of an 11-year-old boy with pulmonary arterial hypertension (PAH) and junctional ectopic tachycardia associated with CAEBV. The patient did not have any major symptoms attributed to CAEBV, such as fever, lymphadenopathy or splenomegaly when the PAH developed. Mild liver dysfunction was found at the first examination, and it persisted. Two years after the PAH symptoms appeared, CAEBV was evident, based on deteriorated liver function, hepatosplenomegaly, and coronary artery aneurysms. CAEBV should be considered as a cause of secondary PAH, particularly when liver dysfunction coexists.

Isorhythmic atrioventricular dissociation in Labrador Retrievers.

BACKGROUND: Isorhythmic atrioventricular dissociation (IAVD) is a rhythm disturbance in which atria and ventricles are driven by independent pacemakers at equal or nearly equal rates. OBJECTIVES: To describe electrocardiographic and electrophysiologic features of IAVD in a group of 11 Labrador Retrievers and its possible correlation with focal junctional tachycardia (FJT). ANIMALS: Between December 2004 and October 2010, medical records of 11 Labrador Retrievers with surface electrocardiographic findings compatible with IAVD were retrospectively analyzed. METHODS: Twelve-lead surface electrocardiograms, thoracic radiographs, and echocardiographic findings of each dog and electrophysiologic mapping results of 3 dogs were retrospectively analyzed. RESULTS: In 10 of 11 dogs, the ECG pattern revealed the presence of IAVD with type I synchronization. In 5 of 10 dogs, IAVD with type I synchronization was interrupted by periods of junctional tachycardia with 1 : 1 ventriculo-atrial conduction. One of 11 dogs presented IAVD with type II synchronization. The ECG diagnosis of IAVD with type I and type II synchronization, and junctional rhythm with 1 : 1 ventriculo-atrial conduction was confirmed in 3 of 11 dogs with endocardial mapping in which the diagnosis of focal junctional tachycardia was made. CONCLUSION AND CLINICAL IMPORTANCE: IAVD with type I synchronization is more common than IAVD with type II synchronization in Labrador Retrievers, and a correlation between IAVD and FJT can be hypothesized.

Transplacental fetal therapy for junctional ectopic tachycardia.

Junctional ectopic tachycardia (JET) is a rare type of tachyarrhythmia. A 39-year-old woman was transferred to our hospital for fetal tachyarrhythmia at 32 weeks' gestation. Fetal cardiac sonography revealed atrial and ventricular rates of 120-130 and 175-230 bpm, respectively, without 1:1 atrioventricular relationship. As ventricular tachycardia was considered to be the most probable diagnosis, transplacental therapy with digoxin and sotalol was done with partial response. Diagnosis of JET was made after birth. Although fetal JET is rare and prenatal diagnosis and treatment of this condition is still a challenge, differential diagnosis of fetal tachyarrhythmia should include this disorder.

A case of congenital junctional ectopic tachycardia: diagnosis and successful radiofrequency catheter ablation in infancy.

It is difficult to make a definitive diagnosis of congenital junctional ectopic tachycardia (JET) in utero. We report a case in which congenial JET was suspected by fetal M-mode echocardiography. Fetal M-mode tracing of the atria and ventricle clearly showed a gradual acceleration of ventricular activity at the beginning of tachycardia, the warming-up sign of ectopic tachycardia, which was followed by simultaneous contractions of atrium and ventricle. This report also describes successful emergent radiofrequency catheter ablation of congenital JET in infancy with preservation of normal AV nodal conduction for this patient.

Prenatal diagnosis of junctional ectopic tachycardia.

The congenital form of junctional ectopic tachycardia has never been reported during the prenatal period. We describe a case in which the diagnosis could be ascertained in utero with the superior vena cava/ascending aorta Doppler approach. The diagnosis was based on the evidence of ventricular tachycardia with atrioventricular (AV) dissociation and the simultaneous occurrence of atrial and ventricular contractions during an episode of tachycardia with 1:1 AV relationship.