Ripple map guided catheter ablation targeting abnormal atrial potentials during sinus rhythm for non-paroxysmal atrial fibrillation

Impact of anisotropic conduction and premature atrial contraction on the fractionated atrial potentials

Background

Fractionated atrial potential (FAP) during sinus rhythm (SR) may be a new target for ablation of atrial fibrillation (AF). However, the effects of the direction of activation and premature atrial contraction (PAC) on FAP is unknown. Therefore, we examined the impact of anisotropic conduction and PAC on the distribution and areas of FAP.

Methods

FAP map in the left atrium was created in 40 patients with AF before ablation. The distribution and areas of FAP were compared during SR, distal coronary sinus (CS) pacing (S1) and extrastimulus (S2), and paced PAC after SR. FAP was defined as a potential with four or more fragmented deflections.

Results

FAPs during SR were found in the right and mid-anterior walls and septum in most patients. During S1 compared to SR, FAPs significantly decreased in the right and mid-anterior walls, appendage, septum, and right inferior wall, while significantly increased in the lateral wall. During S2 compared to S1, FAPs significantly increased in the mid anterior and right and mid posterior walls. During PAC compared to SR, FAPs significantly decreased in the right and mid anterior walls and roof, while significantly increased in the left anterior, left inferior and lateral walls. A rotational activation pattern at the FAP area during CS pacing was observed in 12 patients (30%), mostly in the left inferior wall.

Conclusions

The distribution and areas of FAP vary with anisotropic conduction and extrastimulus. Therefore, FAP should be evaluated not only during SR but also during extrastimulus from the distal CS.

Abnormal Atrial Potentials Recorded During Sinus Rhythm or Pacing Represent Substrates for Reentrant Atrial Tachycardia

BACKGROUND

Abnormal atrial potentials (AAPs) recorded during sinus rhythm/atrial pacing may indicate areas of slow conduction capable of supporting reentrant atrial tachycardia (AT). Therefore, we sought to examine the relationship between AAPs and AT circuits.

METHODS

One hundred twenty-three reentrant ATs in 104 patients were analyzed. AAPs, consisting of fragmented potentials and split potentials, were assessed using the Rhythmia LUMIPOINT algorithm.

RESULTS

There was 93±13% overlap between areas with AAPs during sinus rhythm/atrial pacing and areas of slow conduction along the reentry circuit during AT. The cumulative area of AAPs was smaller in patients with localized-reentrant ATs compared with anatomic macro-reentrant ATs (20.0 [14.6-30.5] versus 28.9 [21.8-35.6] cm2; P=0.021). Patients with perimitral ATs had larger areas of AAPs on the lateral wall whereas patients with roof-dependent ATs had larger areas of AAPs on the roof and posterior wall (P≤0.018 for all comparisons). The patchy scar that was associated with localized-reentrant AT exhibited a larger area of AAPs at its periphery than the scar that did not participate in localized-reentrant AT (3.1 [2.4-4.5] versus 1.0 [0.7-1.6] cm2; P<0.001).

CONCLUSIONS

AAPs recorded during sinus rhythm/atrial pacing are associated with areas of slow conduction during reentrant AT. The burden and distribution of AAPs may provide actionable insights into AT circuit features, including in cases in which ATs are difficult to map.

Ripple Frequency Determined via a Novel Algorithm Is Associated With Atrial Fibrillation Termination and Freedom From Atrial Fibrillation

Background

Persistent atrial fibrillation (AF) is a complex arrhythmia, and attaining freedom from AF with ablation has been challenging.

Objectives

This study evaluated a novel CARTO software algorithm based on the CARTO Ripple map for AF termination and 18-month freedom from AF.

Methods

Consecutive patients who underwent first-time ablation for persistent AF were included. A high-density Ripple map was created using a Pentaray catheter. Following PVI, ablation was performed at locations with rapid Ripple activations, a protocol previously described by us. Patients were followed for 18 months to assess rhythm outcomes. A retrospective analysis was performed using the CARTO Ripple frequency software algorithm. The Ripple frequency algorithm quantifies amplitude changes in the bipolar electrogram.

Results

A total of 115 AF maps were analyzed from 84 patients (mean age 65.9 years, 63.1% men). The top quartile of Ripple frequency corresponded to a visual reference with 96.7% sensitivity and 91.1% specificity. AF terminated during ablation in 88.1% of patients: pulmonary vein antrum alone (14.9%) or pulmonary vein plus nonantral sites (85.1%). The top quartile of Ripple frequency was present in nonantral areas associated with AF termination with 90.2% sensitivity and 86.5% specificity. After 14.0 ± 6.5 months and 1.2 ± 0.4 ablations, 78 (92.9%) of 84 patients were free of AF, and 79.8% were free of any atrial arrhythmia.

Conclusion

A novel algorithm for automated analysis of CARTO Ripple frequency demonstrated good sensitivity and specificity for detecting atrial regions in persistent AF in which ablation is associated with frequent AF termination and freedom from AF during follow-up.