Comparison of Echocardiographic Parameters of Left Atrial and Ventricular Function between Young Stroke vs Lone Atrial Fibrillation vs Healthy Controls

Abstract

Background: Stroke is one of Australia's leading causes of morbidity and mortality with a significant percentage classified as cryptogenic. The nature and aetiology of cryptogenic stroke remains elusive, with a proportion believed to be cardio-embolic secondary to subclinical paroxysmal atrial fibrillation (AF). We aim to gain mechanistic insights into the pathophysiology of cryptogenic stroke in the young by comparing cardiac structural and functional differences in patients with young stroke, lone AF and healthy controls. Methods: Patients aged ≤60 years with diagnosed ischaemic stroke admitted to our institution (2014–2018) without traditional cardiovascular risk factors were compared to age-matched patients admitted with a diagnosis of paroxysmal lone AF. Both groups were compared to cardiovascular disease-free controls. 30 patients in each cohort were recruited. Echocardiographic parameters were analysed; LV and LA strain assessment was performed offline using vendor-independent software (TomTec Arena, Germany v4.6). Results: There were no significant differences in LV parameters (LVEF, LV endoGLS) between groups. When comparing lone AF with young stroke patients, indexed LAmax was significantly smaller in stroke patients (26 ± 7 vs 22 ± 7; p = 0.024). LA strain was significantly lower in AF patients compared to stroke patients (21.6 ± 5.4 vs 30.7 ± 4.9; p < 0.0005). Interestingly, LA strain in stroke patients was significantly lower compared to the healthy cohort (30.7 ± 4.9 vs 34.9 ± 6.2; p < 0.005). Conclusions: A stepwise reduction in LA strain was appreciated between controls, young stroke and lone AF. This may indicate dynamic LA remodelling occurring in the young stroke population and suggest a shared causal mechanism for stroke development in this group.