SAT-401 Heart Ventricular Function In Hospitalized Patients With Severe Hypothyroidism

Abstract Disclosure: J. Lado-Abeal: None. I. Munir: None. K. Al-Zubaidi: None. S.S. Mohammed: None. A. Guo: None. P. Surampudi: None. S. Tadisina: None. R. Bhattacharya: None. M. Ginzo-Villamayor: None. E. Fernandez-Rodriguez: None. P. Perez-Castro: None. C. Tejera-Perez: None. Y. Xiang: None. T. Smith: None. A. Fernandez-Pombo: None. Background: The role of thyroid hormones in controlling heart chronotropy is well established; conversely, the clinical significance of thyroid hormone inotropic role remains contentious. Patients with severe hypothyroidism and myxedema coma provide a unique opportunity to evaluate the clinical impact of a prolonged lack of thyroid hormone supply for the heart. Additionally, patients admitted to intensive care units (ICU) with severe hypothyroidism often have concomitant conditions causing non-thyroidal illness syndrome, which further reduces the supply of thyroid hormones to the heart. This study evaluated heart ventricular contractility via transthoracic echocardiogram (TTE) and speckle-tracking echocardiography (STE) in a large cohort of patients with severe hypothyroidism. Methods: A multicenter, cross-sectional study of patients admitted to ICUs with severe clinical hypothyroidism. All patients underwent a TTE to evaluate left ventricular ejection fraction (LVEF) (normal range > 50%). STE and Tomtec software assessed the myocardial deformation and measured the left-ventricular (LV) global longitudinal strain (GLS) (nr -24% to -16%) and right-ventricular (RV) GLS (nr -35% to -17%). Exclusion criteria included ischemic coronary artery disease, cardiac arrest, implanted cardiac device, atrial fibrillation, amiodarone treatment, receiving hemodialysis, history of cardiotoxic chemotherapy, alcohol withdrawal, urgent surgery, or septic shock at admission. Results: A cohort of 98 patients (mean age 56.4±14.6 years), with a greater predominance of females (n 64; 65.3%). Myxedema coma was diagnosed in 18 cases (18.4%). Median serum TSH at admission was 115.7 mIU/L (range 41.9-500.0), without differences in patients with myxedema coma vs. the remaining study population. Myxedema coma was associated with greater QT and PR intervals. Mean LVEF was 52.8±14.0%, LVGLS -13.3±4.2%, and RVGLS -17.9±5.3%, with no differences regarding gender or the presence of myxedema coma. Low LVEF (<50%) was observed in 26% of cases; LVGLS was abnormal (>-16%) in 73% and RVGLS (>-17%) in 34% of the cases. A tendency towards greater TSH levels was observed in patients with impaired LVEF (p=0.076) and left ventricular GLS (p=0.091). Mortality during hospitalization occurred in three (3.1%) patients, all with normal LVEF. Conclusions: Severe hypothyroidism is associated with heart ventricular muscle dysfunction manifested by a high prevalence of patients (>70%) with increased GLS and, clinically, with low LVEF. Presentation: Saturday, July 12, 2025