A simple surgical technique to prevent atrial reentrant tachycardia in surgery for congenital heart disease†.

OBJECTIVES: To present and test a simple surgical technique that may prevent atrial reentrant tachycardia following surgery for congenital heart disease. This arrhythmia is one of the commonest long-term complications of such a surgery. It may occur many years (even decades) after the operation. It is usually explained as a late consequence of right atriotomy, which is an inherent component of many operations for congenital heart disease. Right atriotomy results in a long scar on the right atrial myocardium. This scar, as any scar, is a barrier to electrical conduction, and macro-reentrant circuits may form around it, causing reentrant tachycardia. However, this mechanism may be counterchecked and neutralized by our proposed method, which prevents reentrant circuits around right atriotomy scars. METHODS: The proposed method is implemented after termination of cardiopulmonary bypass and tying the venous purse-strings. It consists of constructing a full-thickness suture line on the intact right atrial wall from the inferior vena cava (IVC) (a natural conduction barrier) to the atriotomy incision. This suture line is made to cross the venous cannulation sites if these are on the atrial myocardium (rather than being directly on the venae cavae). Thus, the IVC, atriotomy and cannulation sites are connected to each other in series by a full-thickness suture line on the atrial wall. If this suture line becomes a conduction barrier, it would prevent reentrant circuits around right atrial scars. This was tested in 13 adults by electroanatomical mapping. All 13 patients had previously undergone right atriotomy for atrial septal defect closure: 8 of them with the addition of the proposed preventive suture line (treatment group) and 5 without (control group). RESULTS: In all 13 cases, the atriotomy scar was identified as a barrier to electrical conduction with electrophysiological evidence of fibrosis (scarring). In the 8 patients with the proposed suture line, this had also become a scar and a complete conduction barrier. In the 5 patients without this suture line, there was free electrical conduction between the IVC and atriotomy scar. CONCLUSIONS: The proposed suture line becomes a scar and conduction barrier. Therefore, it would prevent reentrant circuits around atrial scars and their consequent arrhythmias.

Electroanatomical mapping of the esophagus in circumferential pulmonary vein isolation.

A virtual reconstruction of the geometry of the esophagus was produced using an electroanatomical mapping system and a specially designed catheter in 20 consecutive patients undergoing circumferential pulmonary vein isolation. The course of the esophagus, its motion and its proximity to the predicted lines of application of radiofrequency energy to the left atrium were evaluated. Thirteen (65%) were located centrally (i.e. >10 mm from the ostium), 69 (30%) laterally (i.e. <10 mm from the ostium) and 1 (5%) obliquely. No movements larger than 10 mm occurred during the procedure. Conventionally, the radiofrequency ablation lines are configured such that, in 50% of patients, radiofrequency energy is applied to areas adjacent to the esophagus. In order to decrease the potential risk associated with this procedure, either the position of the ablation lines was altered to bring them closer to the ostium (by 15%) or the power was reduced (by 35%). Although there was no significant movement of the esophagus during the ablation procedure, its course was variable. Consequently, the ablation strategy was altered in a substantial number of cases.

Cartografía electroanatómica del esófago en el aislamiento circunferencial de venas pulmonares / Electroanatomical mapping of the esophagus in circumferential pulmonary vein isolation

Realizamos una reconstrucción virtual de la geometría del esófago con un sistema de cartografía electroanatómica utilizando un catéter específico en 20 pacientes consecutivos sometidos a aislamiento circunferencial de venas pulmonares. Monitorizamos el trayecto esofágico y sus movilizaciones, valorando la proximidad a las líneas de aplicación de radiofrecuencia previstas en la aurícula izquierda. Trece (65%) fueron centrales (> 10 mm de los ostia), 6 (30%) laterales ( < 10 mm) y 1 (5%) oblicuo. No hubo movilizaciones > 10 mm durante el procedimiento. La disposición convencional de las líneas de ablación suponía la aplicación de radiofrecuencia en zonas adyacentes al esófago en el 50% de los pacientes. Intentando reducir el riesgo potencial de estas aplicaciones, se modificó su posición aproximándolas a los ostia (15%) o se disminuyó la potencia (35%). El esófago demuestra una disposición variable sin desplazamientos significativos durante el procedimiento de ablación. Esto implica modificar la estrategia de ablación en un número considerable de casos (AU)

A virtual reconstruction of the geometry of the esophagus was produced using an electroanatomical mapping system and a specially designed catheter in 20 consecutive patients undergoing circumferential pulmonary vein isolation. The course of the esophagus, its motion and its proximity to the predicted lines of application of radiofrequency energy to the left atrium were evaluated. Thirteen (65%) were located centrally (i.e. >10 mm from the ostium), 69 (30%) laterally (i.e. <10 mm from the ostium and 1 5 obliquely no movements larger than 10 occurred during procedure conventionally radiofrequency ablation lines are configured such that in 50 of patients energy is applied to areas adjacent esophagus order decrease potential risk associated with this either position was altered bring them closer by 15 or power reduced 35 although there significant movement its course variable consequently strategy a substantial number cases (AU)

Three-dimensional impedance mapping as an aid to circumferential pulmonary vein isolation in paroxysmal atrial fibrillation.

During circumferential pulmonary vein isolation, radiofrequency lesions are created in the transition zone between the left atrium and the pulmonary veins, outside the ostia, to avoid stenosis. Three-dimensional impedance maps were constructed for 25 patients with paroxysmal atrial fibrillation. In the first 15 patients, impedance was measured inside the pulmonary veins (165.4 +/- 7.5 Omega), the ostium (141.6 +/- 7.3 Omega) and the left atrium (131.09 +/- 8.3 Omega). An impedance of 136 Omega identified the outer limit of the atrium (area under the receiver operating characteristic curve, 0.85). In the subsequent 10 patients, a single operator who was blinded to the anatomic position of the catheter tip was able to determine, by impedance measurement alone, whether the point targeted for radiofrequency ablation was in the left atrium or the ostium of the pulmonary vein. The positive predictive value for identifying the left atrium was 91% and the negative predictive value was 73%. In patients with paroxysmal atrial fibrillation, three-dimensional impedance mapping was helpful in guiding circumferential pulmonary vein isolation.