Enlarged left atrium and decreased left atrial strain are associated with atrial fibrillation in patients with hyperthyroidism irrespective of conventional risk factors

Background: The purpose of this study was to investigate factors associated with AF in patients with hyperthyroidism beyond heart failure (HF), coronary heart disease (CHD), or valvular diseases.Methods: A total of 136 patients (mean age, 52 ± 15 years; 86 [63%] female) who were diagnosed with hyperthyroidism for the first time were enrolled. Patients who had HF, CHD, or significant valvular diseases were excluded. Patients were classified into two groups according to the presence (group 1, n=40) and absence of AF (group 2, n=96). Results: AF occurred in 40 (29%) patients and 23 (58%) of these patients showed paroxysmal AF. Among the symptoms of hyperthyroidism, the most common chief complaint was palpitation (30%). Advanced age, presence of prior cerebrovascular events, and presence of palpitations were associated with AF. Larger left atrial volume index (LAVI), increased left ventricular mass index, and decreased left ventricular ejection fraction (LVEF) and S’ velocity were associated with AF. Among them, presence of palpitations and increased LAVI were independently associated with the occurrence of AF. In addition, strain analysis, decreased LA expansion index (EI), ejection fraction (EF), peak atrial longitudinal strain, contraction strain, and late diastolic strain rate (A sr) and systolic strain rate (S sr) were associated with the occurrence of AF and LAVI.Conclusion: Presence of palpitations and enlarged left atrium were associated with the occurrence of AF in patients with hyperthyroidism irrespective of conventional risk factors. Additional LA analysis revealed that decreased LA function was associated with AF and enlarged left atrium.