Real-time correction of respiratory-induced cardiac motion during electroanatomical mapping procedures

Treatment planning during catheter interventions in the heart is often based on electromechanical tissue characteristics obtained by endocardial surface mapping (ESM). Since studies have shown respiratory-induced cardiac motion of over 5 mm in different directions, respiratory motion may cause ESMs artifacts due to faulty interpolation. Hence, we designed and tested a real-time respiration-correction algorithm for ESM. An experimental phantom was used to design the correction algorithm which was subsequently evaluated in five pigs. A piezo-respiratory belt transducer was used to measure the respiration. The respiratory signal was inserted to the NOGA^®XP electromechanical mapping system via the ECG leads. The results of the correction were assessed by measuring the displacement of a reference point and the registration error of the ESM on a CMR scan before and after correction. In the phantom experiment, the reference point displacement was 6.5 mm before and 1.1 mm after correction and the registration errors were 2.8 ± 2.2 and 1.9 ± 1.3 mm, respectively. In the animals, the average reference point displacement (apex) was reduced from 2.6 ± 1.0 mm before to 1.2 ± 0.3 mm after correction (P < 0.05). The in vivo registration error of the ESM and the CMR scan did not significantly improve. Even though the apical movement appreciated in pigs is small, the correction algorithm shows a decrease in displacement after correction. Application of this algorithm omits the use of the time-consuming respiratory gating during ESM and may lead to less respiratory artifacts in clinical endocardial mapping procedures.