Evaluation of the atrial substrate based on low‐voltage areas and dominant frequencies after pulmonary vein isolation in nonparoxysmal atrial fibrillation

Background This study aimed to evaluate the atrial substrate in the left atrium ( LA ) by low‐voltage areas ( LVA s) and high‐dominant frequencies ( DF s) after circumferential pulmonary vein isolation ( PVI ) in nonparoxysmal atrial fibrillation ( AF ). Methods In 70 patients with nonparoxysmal AF patients (41 persistent AF ), LA voltage maps were created during sinus rhythm by external cardioversion after PVI and DF mapping. The patients were divided into AF ‐free and AF ‐recurrent groups. Results The AF freedom rate without antiarrhythmic drugs was 69.0% after PVI after 1 procedure during a 12‐month follow‐up. There was a significant difference in the LVA (<0.5 mV)/ LA surface area after PVI between the AF ‐free and AF ‐recurrent groups (15% vs 23%, P  = .033). AF freedom was significantly greater in those with LVA s of ≤24% than in those with LVA s of >24% during 12 months of follow‐up (78.6% vs 53.8%, Log‐rank test P  = .020). Fifty‐six (72%) of the 78 high‐ DF sites (≥8 Hz) overlapped with LVA s. Thirty‐one (55%) of 56 high‐ DF sites overlapped with LVA s that existed at LVA border zones. There were no significant differences in number of high‐ DF sites that overlapped with LVA s in the LA between the two groups. However, in persistent AF patients, the max‐ DF value in the LA exhibited a significant difference between the two groups ( P  = .008). Conclusions LVA s were associated with AF recurrences after PVI in nonparoxysmal AF patients and overlapped with many high‐ DF sites. PVI alone may be enough to treat patients with mild‐to‐moderate extent (≤24%) of LVA s.