Use of a 3-dimensional electroanatomical mapping system for catheter ablation of macroreentrant right atrial tachycardia following atriotomy

The purpose of this study was to utilize a 3-dimensional (3D) electroanatomical mapping system (CARTO) to characterize the reentrant circuit in macroreentrant right atrial tachycardia (AT) following right atriotomy. Right atrial mapping was performed during incessant AT in a patient who had a right atriotomy for closure of an atrial septal defect. During AT, the right atrial free wall exhibited a large contiguous area of low bipolar voltage (less than or equal to 0.5 mV, 7.3 cm in length, and 6.3 cm in width). Two discrete scars, showing no electrical potential, were identified within the large low-voltage area. A larger vertical scar (thought to be from the atriotomy) and a smaller second scar (possible inferior vena cava cannulation scar) formed a narrow channel (1.5 cm in width) between these 2 scars. Right atrial activation propagated around the large upper scar, and then propagated through the channel between the 2 scars. A single application of radiofrequency current within the channel eliminated the macroreentrant AT. In conclusion, macroreentrant AT following right atriotomy was associated with 2 discrete scars and utilized the isolated channel between the 2 scars. Ablation within the channel effectively eliminated macroreentrant AT after atriotomy and eliminated the requirement for linear ablation between one or more of the scars and the tricuspid annulus.