Lessons from ablation responses to preferential wavefront in typical atrial flutter.

The heterogeneous conduction properties through the cavotricuspid isthmus (CTI) in typical atrial flutter (AFL) have not yet been well elucidated. We sought to investigate preferential conduction through the CTI and the efficacy of ablation targeting preferential wavefront (PW) guided by ultra-high-resolution mapping. In retrospective study, 28 patients were enrolled. Wavefront propagation patterns through the CTI and ablation responses at the location of PW were evaluated. In the following prospective study, 23 patients with predominant PW across the CTI were enrolled and assigned to the arm of PW prior ablation and the arm of conventional ablation. Five activation patterns were noticed in the retrospective study. The termination sites were exactly located at the PW in 18 of 28 patients (64.3%). The width of the PW in direct termination group was significantly narrower than that in the CL prolongation before termination group (16.6 ± 1.0 mm vs. 23.3 ± 3.4 mm, respectively, p = 0.025). In the prospective study, the voltage of PW region was significantly higher than non-PW regions both from unipolar and bipolar mapping. 21 of 23 patients (91.3%) were terminated at PW. AFL could no longer be induced immediately after termination. The time from radiofrequency application to AFL termination and to achieve bidirectional conduction block was significantly shorter in PW prior ablation arm than that in conventional ablation group (p < 0.05). Ablation targeting the PW first could be more efficient to terminate typical AFL and to achieve the endpoint of bidirectional conduction block.

Wang L ，Ding X ，Ju W ，Chen H ，Gu K ，Li M ，Chen M ，Yang G ... -  《-》

Characteristics of virtual unipolar electrograms for detecting isthmus block during radiofrequency ablation of typical atrial flutter.

Lin YJ ，Tai CT ，Huang JL ，Liu TY ，Lee PC ，Ting CT ，Chen SA ... -  《JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY》

Predictors of acute inefficacy and the radiofrequency energy time required for cavotricuspid isthmus-dependent atrial flutter ablation.

Pérez-Rodon J ，Rodriguez-García J ，Sarrias-Merce A ，Rivas-Gandara N ，Roca-Luque I ，Francisco-Pascual J ，Santos-Ortega A ，Martín-Sánchez G ，Ferreira-González I ，Rodríguez-Palomares J ，Evangelista-Masip A ，García-Dorado D ，Moya-Mitjans À ... -  《-》

A new methodology for atrial flutter ablation by direct visualization of cavotricuspid conduction with voltage gradient mapping: a comparison to standard techniques.

Bailin SJ ，Johnson WB ，Jumrussirikul P ，Sorentino D ，West R ... -  《-》

Ablation of typical atrial flutter guided by the paced PR interval on the surface electrocardiogram: a proof of concept study.

We aimed to assess the novel concept of using the paced PR interval (PRI) on the surface electrocardiogram (ECG) to prove trans-isthmus block after cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl). Consecutive patients with AFl underwent linear radiofrequency ablation of the inferior CTI (6 o'clock). After AFl termination and/or presumed completion of the CTI line, CTI block was proven by atrial pacing by the ablation catheter medial (5 o'clock) and lateral to the line (7 and 9 o'clock). Corresponding PRIs were measured on the surface ECG. CTI block was assumed, if a sudden increase in the PRI was observed by moving the pacing site from 5 to 7 o'clock, and if the latter was longer than at 9 o'clock. Afterwards, bidirectional CTI block was confirmed by differential pacing. Thirty-one patients (mean age 67 ± 16 years, 81% male) underwent CTI ablation, and 18/31 (58%) were in AFl at the time of ablation (cycle length 249 ± 31 ms). Successful CTI block as defined by the PRI method was achieved in 31/31 (100%), and the mean PRIs during pacing at 5, 7, and 9 o'clock were 203 ± 56 ms, 329 ± 70 ms, and 296 ± 66 ms, respectively. Cavotricuspid isthmus block was confirmed in all patients (100%) by coronary sinus pacing with a reversal of the local activation sequence lateral to the isthmus line. The method of PRI analysis on the surface ECG to guide CTI ablation is easy to apply and highly accurate in confirming CTI block. This simple technique enables the novel concept of CTI ablation and proof of block with a single catheter.

Madaffari A ，Krisai P ，Spies F ，Knecht S ，Schaer B ，Kojic D ，Kühne M ，Sticherling C ，Osswald S ... -  《-》