Quantitative tissue-tracking cardiac magnetic resonance (CMR) of left atrial deformation and the risk of stroke in patients with atrial fibrillation

Background-Recent evidence suggests that left atrial (LA) dysfunction may be mechanistically contributing to cerebrovascular events in patients with atrial fibrillation (AF). We investigated the association between regional LA function and a prior history of stroke during sinus rhythm in patients referred for catheter ablation of AF. Methods and Results-A total of 169 patients (59±10 years, 74% male, 29% persistent AF) with a history of AF in sinus rhythm at the time of pre-ablation cardiac magnetic resonance (CMR) were analyzed. The LA volume, emptying fraction, strain (S), and strain rate (SR) were assessed by tissue-tracking cardiac magnetic resonance. The patients with a history of stroke or transient ischemic attack (n=18) had greater LA volumes (V_max and V_min; P=0.02 and P<0.001, respectively), lower LA total emptying fraction (P<0.001), lower LA maximum and pre-atrial contraction strains (S_max and S_preA; P<0.001 and P=0.01, respectively), and lower absolute values of LA SR during left ventricular (LV) systole and early diastole (SR_s and SR_e; P=0.005 and 0.03, respectively) than those without stroke/transient ischemic attack (n=151). Multivariable analysis demonstrated that the LA reservoir function, including total emptying fraction, S_max, and SR_s, was associated with stroke/transient ischemic attack (odds ratio 0.94, 0.91, and 0.17; P=0.03, 0.02, and 0.04, respectively) after adjusting for the CHA₂DS₂-VASc score and LA V_min. Conclusions-Depressed LA reservoir function assessed by tissue-tracking cardiac magnetic resonance is significantly associated with a prior history of stroke/transient ischemic attack in patients with AF. Our findings suggest that assessment of LA reservoir function can improve the risk stratification of cerebrovascular events in AF patients.