PO-01-106 ATRIAL ISOCHRONAL LATE ACTIVATION MAPPING KEEPS THE DIAPHRAGM ALIVE

Abstract

Isochronal late activation mapping (ILAM) is a well-established mapping method for ventricular arrhythmias. However, the role of ILAM mapping during atrial arrhythmias is less clear. This case provides an example of ILAM use during right atrial flutter ablation using the high-density Optrell (Biosense Webster, CARTO) catheter in a patient with congenital heart disease. N/A N/A A 27-year-old female with D-transposition of the great arteries status post Nikaidoh (arterial switch operation with ventricular septal defect repair, pulmonary valve replacement, and typical atrial flutter status post ablation presented with SVT and was referred for catheter ablation. During EPS, conventional activation mapping of fleeting atrial flutter was attempted utilizing the Optrell catheter, which localized the region of interest to a large section of the inferior posterolateral RA, which also had diffuse phrenic nerve capture (figure 1, panel A). However, during periods of sinus rhythm, ILAM and voltage mapping was conducted that demonstrated a distinct, confined, region of isochronal crowding along the mid-posterolateral right atrium, distant from the phrenic nerve (figure 1, panel B). The ILAM site was addressed with catheter ablation rendering the atrial flutter non-inducible with preservation of phrenic nerve function. The patient has remained free of atrial arrhythmias in the 6 months period since the ablation. The application of ILAM is well-established for ventricular tachycardia, however, its role in atrial arrhythmias is less clear. ILAM may be especially useful in adults with congenital heart disease given the complexity of atrial arrhythmia and the benefit of ablation in this unique population. Novel high-density mapping catheters, such as Optrell, allow for rapid and granular voltage data and translate well to ILAM regions within the atrium. Application of ILAM within atrial substrate, particularly for congenital heart disease which predisposes to higher recurrence rates, may improve both recurrence rates and safety, like in this case where the use of this method allowed avoiding ablation on the phrenic nerve.