Ablation of atypical atrial flutter guided by the use of concealed entrainment in patients without prior cardiac surgery

Ablation of Atypical Atrial Flutter, Introduction: Mapping techniques have not been systematically evaluated with respect to atypical atrial Butter (A F) not involving the inferior vena cava isthmus, The purpose of this study was to assess prospectively the use of concealed entrainment (CE) in mappin g of AF and to assess the clinical benefit of ablation of clinically releva nt atypical AF, Methods and Results: In seven consecutive patients without prior cardiac su rgery presenting with atypical AF, mapping was performed in the right and, if necessary, left atrium, At sites with CE, radiofrequency energy was deli vered. In a posthoc analysis, the endocardial activation time, stimulus-flu tter wave (F) interval, presence of split potentials and diastolic potentia ls, and postpacing interval were assessed, and effective sites were compare d to ineffective sites. A total of 22 forms of atypical AF either could be induced or were present at the time of the study. Eleven of the 13 targeted atypical AFs (85%) were successfully ablated, The positive predictive valu e of CE increased from 45% to 75% in the presence of matching electrogram-E and stimulus-P intervals or if Butter terminated during entrainment pacing , and to 88% in the presence of split atrial electrograms or diastolic pote ntials. During short-term clinical follow-up, none of the patients had recu rrence of the ablated AF, However, the majority of patients required either medication for atrial fibrillation or repeated interventions for new forms of AF. Conclusion: Mapping and ablation of atypical AF is Feasible if sites with C E can be identified. However, the clinical benefit of successful ablations in patients with atypical Butter appears to be limited.