16-23: Endocardial voltage mapping of pulmonary veins with a new ultra high-resolution electroanatomical mapping system to evaluate atrial myocardial extensions

Introduction: Atrial fibrillation (AF) is triggered by arrhythmogenic foci originating from atrial muscular sleeves (MEs) that extend into the pulmonary veins (PVs). We evaluated endocardial voltage maps of PV as a surrogate parameter for the extent of MEs in subjects with AF by a novel high density mapping system (Rhythmia -Boston Scientific).

Methods: 15 consecutive pts underwent catheter ablation for AF using Rhythmia in conjunction with the Orion mini-basket catheter, which was utilized to create an electroanatomic shell of the LA and PVs during Sinus rhythm. Each PV was divided into an anterior and posterior portion, and the maximal distance between the ostium and the absence of electrical potentials (noise level <0.03 mV) in PVs was considered as a surrogate parameter for the extent of MEs .

Results: Mean pts age was 61 ± 6 years. 64 % had paroxysmal and 36% persistent AF. PV anatomy was normal in all patients. Mean voltages in PVs were as follows: RSPV 4,3 ± 1,4mV, RIPV 5,4 ± 1,4mV, LSPV 6,6 ± 1,7mV and LIPV 6,3 ± 3mV (p = ns), respectively.

MEs were present in all pts but one, and more prevalent in the anterior side of the PVs. The area of MEs was significantly larger in the superior compared to the inferior veins (10,6 ± 4,3 vs. 7,1 ± 3,9 cm2, p = 0,004).The maximum length of MEs was as follows:

Conclusion: In this pilot study using a new ultra high-resolution electroanatomical mapping system, endocardial voltage maps of PVs as a surrogate parameter of ME among patients with AF well correspond to previous data from histopathological studies. Further studies in larger cohorts are warranted to evaluate the significance of these findings.