Left atrial and ventricular strain and extracellular volume fraction in patients with paroxysmal and persistent atrial fibrillation

Abstract

To investigate cardiac MR (CMR) parameters, including left atrial (LA)/left ventricular (LV) volume, function, and extracellular volume fraction (ECV), in persistent and paroxysmal AF after catheter ablation and to evaluate the relationship between ECV and CMR parameters in AF patients. Participants comprised 41 patients with AF (persistent AF, n = 25; paroxysmal AF, n = 16) who underwent CMR study including cine-CMR, late gadolinium enhancement (LGE) CMR, and pre- and post-contrast T1 mapping within a week after restoration of sinus rhythm by catheter ablation and 18 matched controls. LA/LV volume and function and LV-ECV were determined by cine-CMR and T1 mapping, respectively. LA reservoir, conduit, and contractile strains (εR, εCD, and εCT) were determined by feature tracking. LV-ECV in patients with persistent AF (29.6 ± 3.2%) was significantly higher than that in controls (27.0 ± 1.9%, p < 0.01), and no significant differences were seen in ECV between the patients with persistent AF and paroxysmal AF and between patients with paroxysmal AF and controls. In patients with AF, univariate linear regression analyses showed that ECV correlated significantly with LV end-systolic volume index (ESVI) (p = 0.03), εR (p = 0.01), and εCD (p = 0.005). Stepwise multivariate analysis, including LV ESVI, εR and εCD as variables, revealed that εCD was independently associated with ECV (standardized β = -0.39, p = 0.009). Patients with persistent AF had higher LV-ECV than controls. LA εCD was independently associated with increased ECV in patients with AF. These results suggest advanced LV fibrosis in patients with persistent AF and that CMR LA strain analysis can predict the severity of LV fibrosis in patients with AF.

Keywords: Atrial fibrillation; Conduit strain; Contractile strain; Extracellular volume fraction; Feature tracking; Reservoir strain.