MAPPING REENTRY AROUND ATRIOTOMY SCARS USING DOUBLE POTENTIALS

Supraventricular arrhythmias, often seen in patients after cardiac sur gery, may be associated with scars produced in the atria at the time o f surgery. Double potentials, found in the presence of functional or a natomical block, can define the limits and critical regions of a reent rant circuit associated with the atriotomy scars. We describe six pati ents with seven distinct atrial tachycardias in whom atriotomy scars w ere successfully mapped during intraatrial reentry utilizing the prese nce and interelectrogram relationship of observed double potentials. T he reentrant circuit was mapped in all patients by following the relat ionship between double potentials along the surgical scar, assuming th at they would be widely split in the middle of the scar and merge into a single continuous fractionated potential at the apex of the scar. A t this site, atrial pacing was performed to entrain the tachycardia an d confirm the participation of the atriotomy scar in the clinically re levant atrial tachycardia. Radiofrequency ablation was performed from the site of electrogram fusion to the nearest anatomical obstacle. Fiv e of seven atrial tachycardias were successfully ablated utilizing thi s technique over a mean follow-up of 10 months. We proposed that these double potentials and their interelectrogram relationship are an effe ctive means of mapping atriotomy scars and guiding successful radiofre quency ablation.