943-8 Does Radiofrequency Ablation of the Medial Isthmus for Atrial Flutter Modify AV Nodal Function?

Ablation of atrial flutter has been shown to be safe and effective, but little is known about the effect of the ablation procedure on AV nodal function. In 28 patients (21 males, mean 55±14 yo, 13 with coronary artery disease) who underwent successful ablation of typical atrial flutter, including 19 (68%) also presenting with atypical flutter, retrograde and antegrade AV nodal function were measured before and after the procedure. RF ablation was achieved by applying linear lesions across the medial isthmus of the right atrium from the tricuspid annulus to coronary sinus ostium and then to the inferior vena cava ostium. Additional linear lesions were also made across the middle portion of the isthmus from the tricuspid annulus to the inferior vena cava ostium. This ablation approach should effectively isolate the posterior input generated by the crista terminalis to the AV node, Ablation was successful in all patients and no patient developed complete heart block. Incidental dual AV nodal function was eliminated in 3 of 4 patients. Pre- and post-ablation AV nodal function are as follows:PAAHHVAnt ERPAnt FRPAnt BlockRet BlockPre RF45±10B4±3651±9337±73444±61365±97476±178PostRF47±1187±3250±9321±79432±62354±81471±179p value0.40.760.920.670.70.60.94