High Incidence of Short-term Subsequent Atrial Fibrillation Following Restrictive Filling Mitral Flow Profile in Patients without Structural Heart Disease.

PURPOSE: This study investigated the implications of a restrictive filling (RF) mitral flow profile on the frequency of short-term subsequent atrial fibrillation (AF) in cases without thrombotic conditions during routine transthoracic echocardiography (TTE). METHODS: A TTE database was retrospectively analyzed from 2015 to 2023 (n = 123,210). We enrolled middle-aged and older adults (≥50 years) with RF mitral flow (the ratio of the early to atrial mitral inflow peak velocities [E/A ratio] ≥2), normal sinus rhythm during the TTE study, and a large left atrial (LA) dimension (≥40 mm) excluding those with structural heart disease and depressed left ventricular ejection fraction. Ad hoc analyses of LA emptying fraction (LAEF) and LA longitudinal strain during the reservoir phase (LASr) were performed. We calculated the ratio of LASr to LAEF (LASr/LAEF) for the discrepancy between LAEF and LASr. RESULTS: The cohort comprised 163 cases (0.13%, 163/123,210) recruited from 3788 cases with RF mitral flow profile (3.1%, 3788/123,210). Subsequent AF was frequently confirmed in this cohort (14.7%, 24/163). LAEF ≤25.9% was selected as a predictor (P = 0.023, odds ratio: 5.547) in a logistic model, while LASr/LAEF ≥0.65 was a predictor in another model (P = 0.020, OR: 3.68). CONCLUSIONS: The RF mitral flow profile is rare but may indicate short-term subsequent AF. Among TTE parameters, low LAEF and increased LASr/LAEF were the predictors. Atrial stunning might play a significant role.