Atrial Pace Mapping Using Intracardiac Pattern Matching: Feasibility and Accuracy

Sven Willert (Kiel)1, T. Demming (Kiel)1, V. Maslova (Kiel)1, A. Zaman (Kiel)1, J. Popara (Kiel)1, L. T. Nicholson (Kiel)1, L. Sprenger (Kiel)1, L. Kleinhans (Norderstedt)2, O. Jahn (Norderstedt)2, D. Frank (Kiel)1, E. Lyan (Kiel)1

1Universitätsklinikum Schleswig-Holstein Innere Medizin III mit den Schwerpunkten Kardiologie, Angiologie und internistische Intensivmedizin Kiel, Deutschland; 2Biostar Webster - Johnson & Johnson Medical GmbH Norderstedt, Deutschland


Introduction: Pace mapping of atrial arrhythmia is a method to localize the origin of usually focal arrhythmias that are unstable or not persisting during EP-study and, therefore not eligible for LAT-Mapping. The technique applies pattern matching of p-waves from surface-electrocardiogram (sEKG) as well as intracardiac signals during atrial tachycardia and pacing from the site of the suspected origin. The CARTO® 3 system Version 7.2 (Johnson&Johnson) applies an automated algorithm for intracardiac pace mapping (ICPM) using the unipolar signal of the reference electrode, usually located in the coronary sinus. 


Methods: We examined 12 consecutive patients undergoing RF pulmonary vein isolation (PVI). We performed local pacing at the anterior and posterior wall of the left atrium (LA) and the posterior and lateral wall of the right atrium (RA). The first pacing point was defined as the reference pacing site (RPS). The ICPM algorithm was applied to calculate the similarity of the IC pattern of the RPS to the IC pattern across various distances. The maps, including mesh, point locations and IC pattern similarity of each point, were exported for further analysis in the Python environment. The areas were calculated for the 5% similarity strata.

Figure 1. A: IC Pattern pace mapping of the focal origin at the posterior wall of left atrium. 

B: Area of >95% of similarity at different regions of left and right atrium. Note the extensive area of high pattern similarity at RA lateral wall, which is not feasible for precise ablation. 


Statistical evaluation revealed that the areas demonstrating a 95% or higher pattern similarity were not uniformly distributed between focal origins across different atrial regions and pacing directions. Particularly, significant differences were identified between the RA lateral wall and the other map regions. Pairwise comparisons after the Kruskal-Wallis test,  

with Bonferroni correction, have yielded the following results: Posterior wall of LA when compared to the RA lateral wall (p = 0.0316), the anterior wall of LA when compared to the RA lateral wall (p=0.0186) and between RA posterior and RA lateral wall (p = 0.0425). These findings indicate a variation in the accuracy of intracardiac pattern matching, with certain areas showing greater precision than others. The area of 95% pattern similarity less than 2 cm2 may be considered acceptable for further catheter ablation. Notably, an outlier was observed in the posterior RA region, suggestive of anomalous pattern-matching performance in this specific instance. (Figure1).

Table 1. Statistical results


LA posterior

LA anterior

RA posterior

RA lateral

Average (A95+)

1.29 cm2

0.76 cm2

1.2 cm2

6.74 cm2

Median (A95+)

1.48 cm2

0.62 cm2

0.60 cm2

5.68 cm2


0.06 cm2

0.08 cm2

1.49 cm2

4.28 cm2


2.14 cm2

2.31 cm2

4.41 cm2

12.5 cm2


0.76 cm2

0.15 cm2

0.38 cm2

2.89 cm2


2.01 cm2

1.06 cm2

1.19 cm2

11.1 cm2

Conclusion: The intracardiac pattern matching for atrial arrhythmias employing the CARTO-ICPM algorithm is feasible with acceptable accuracy except for the lateral regions of the right atrium. This might be explained by the larger distance to the referent catheter in the coronary sinus and the preferred conduction direction in the crista terminalis.  Enhancing localization accuracy may necessitate the adjunctive use of surface ECG-pace mapping or the deployment of an additional multipolar intracardiac reference catheter in the lateral RA. 

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