Advanced AF
In addition to the CONVERGE post-hoc analysis for LSPAF, other studies have demonstrated favorable success to eliminate atrial arrhythmia or maintain normal sinus rhythm in patients with longstanding persistent AF.23,29Classification of AF by duration alone is arbitrary and can be challenging based on incomplete patient history or available rhythm monitoring. There is emerging evidence that other factors associated with advanced AF may characterize patients who could benefit from Hybrid Convergent ablation.23,29
Left atrial (LA) size has been shown to be related to the recurrence of AF after endocardial ablation.30 Most studies have defined enlargement by atrial diameter although a meta-analysis of 22 studies that due to the asymmetry of the LA and thus LA dilation, LA diameter may be an underestimate of size and LA volume is more accurate in predicting AF recurrence and even new onset AF.31 Because the imaging modalities vary in the precision of their estimates of left atrial size, the mean difference in larger atria associated with the risk of AF is actually quite small so this must be a consideration in determining the accuracy of LA size measurements. Of the 22 studies in the meta-analysis by Zhuang, et al, the mean LA diameter reported at baseline was 34.3-49mm, partly beyond normal range. Only 3 studies were identified that solely examined non-paroxysmal AF, for a total of 143 patients. The mean atrial size in those studies ranged from 45-49mm.30 The CONVERGE trial allowed patients with left atrial diameter up to 6.0 cm, with the mean left atrial diameter in the Hybrid Convergent arm of 4.4 cm (44mm).32 With an increased risk of developing recurring AF, patients with enlarged left atria might be best served by Hybrid Convergent ablation versus a catheter ablation that may result in recurrences and repeat ablations.