P3790Left ventricular stiffness assessed by diastolic wall strain predicts infrequent atrial fibrillation

Abstract

Abstract Background Left ventricular (LV) stiffness as the passive LV filling property in the LV diastolic function has been reported to be related with the prevalence of atrial fibrillation (AF). On the other hand, a novel insertable monitoring (ICM) system is a powerful tool to detect AF with rare appearance in patients with embolic stroke of undetermined source (ESUS). We investigated whether the LV stiffness assessed by diastolic wall strain (DWS) predicts infrequent atrial fibrillation. Methods Fifty-five patients (41 males, 68±14 years) who underwent ICM implantation for ESUS (n=19) or unexplained syncope (n=36) were studied. DWS, left atrial (LA) stiffness and other measurements were assessed using transthoracic echocardiography before the ICM implantation. DWS was calculated from the M-mode echocardiographic measurement of the LV posterior wall thickness at end-systole (PWs) and end-diastole (PWd) during sinus rhythm, and DWS was defined as PWd/PWs. LA stiffness index was defined as the ratio of E/e' to LA peak strain. Results AF was detected in 20 patients (36%) during the follow-up periods (280±243 days). Patients with AF showed reduced DWS (0.30±0.07 vs. 0.41±0.08, p<0.0001), larger LA volume index (39.0±10.9 vs. 32.3±9.0, p=0.0174), and higher age (74.6±10.4 vs. 64.6±14.9, p=0.0105). On the other hand, LA stiffness index, LA function (reservoir, booster, and conduit function estimated by LA volume), and LV relaxation function (E wave, E/A ratio, deceleration time) were not associated with detection of AF. There was no difference on AF detection rate between ESUS and unexplained syncope (26% vs. 42%, p=0.2604). On multivariate analysis, DWS was only independently associated with detection of AF (p<0.0001, OR 5.647 for each 0.1 decrease in DWS, 95% CI 1.084–1.338). Moreover, patients with reduced DWS (<0.38) had a higher risk of incidences of AF than patients with preserved DWS (figure). Figure 1 Conclusions LV stiffness assessed by DWS predicts infrequent AF. Reduced LV stiffness rather than LA dysfunction or LV relaxation dysfunction may be the main cause of AF in the early stages.