Incessant atrial flutter after device closure of atrial septal defect: successful radio frequency ablation.

A four-month-old baby presented with failure to thrive and congestive cardiac failure precipitated by a lower respiratory tract infection. He was found to have a large ostium secundum atrial septal defect measuring 18 mm. This was successfully closed percutaneously by a device (Blockaid). A month after the device deployment the child developed typical atrial flutter. Despite rate control drugs the ventricular rate remained l40/min over the next several months. In view of the incessant atrial flutter with fast ventricular response, the child underwent radiofrequency ablation at the age of 2 years. An isthmus block was created which successfully terminated the tachycardia.

'Hibernating' accessory pathway.

A 13-year-old boy presented with recurrent narrow QRS tachycardia from which he had been suffering for one year. An electrophysiology study revealed a concealed left lateral accessory pathway with inducible orthodromic atrioventricular re-entry tachycardia using the same pathway. The accessory pathway was ablated in January 2004. After the ablation, atrioventricular block was demonstrated (with adenosine), as was ventriculo-atrial block, and the patient had paroxysmal tachycardia one month later. This time, however, the electrocardiogram in sinus rhythm showed a negative delta wave in V1, suggestive of a right-sided accessory pathway. Another electrophysiology study showed no conduction across the left accessory pathway found earlier. The right accessory pathway, which had 'emerged' after the ablation, had an antegrade effective refractory period of 440 msec and a retrograde effective refractory period of <250 msec. Orthodromic atrioventricular re-entry tachycardia using this accessory pathway was easily inducible. The tricuspid annulus was mapped and the second accessory pathway was localized to the right anterolateral region. This was ablated successfully. This is a unique instance of a symptomatic 'hibernating' accessory pathway emerging in adolescence.

'Rescue' radiofrequency ablation for atrial tachycardia presenting as cardiomyopathy in pregnancy.

A young primiparous lady presented with drug-refractory atrial tachycardia which had led to cardiomyopathy. Three attempts with electrical cardioversion were also unsuccessful. She was rescued by radiofrequency ablation.

Radiofrequency ablation of incessant orthodromic tachycardia in a young child with a univentricular heart.

The incidence of supraventricular tachycardia is high in infants and children with congenital heart disease. We report a case of incessant orthodromic tachycardia in a child with a univentricular heart, which was successfully treated with radiofrequency ablation.

Radiofrequency ablation of incessant atrial tachycardia in an infant.

Ectopic automatic atrial tachycardia, an uncommon type of supraventricular tachycardia in children and adults, has been reported to be resistant to medical therapy unlike reentrant supraventricular tachycardia. We report a case of incessant atrial tachycardia in an infant, which was successfully treated with radiofrequency catheter ablation.

Catheter ablation of atrial tachycardia using a real-time position management mapping system.

Catheter ablation for atrial tachycardia is limited by its low success rate and prolonged procedure time because of difficulties in mapping the site of the tachycardia. A new three-dimensional mapping system, the Cardiac Pathways mapping system, using an ultrasound transducer, has recently become available. We report a case of focal atrial tachycardia ablation with this system.