Heart ventricular function in hospitalized patients with severe hypothyroidism and myxedema coma

The clinical relevance of thyroid hormone-mediated inotropic effects in humans remains uncertain.

We evaluated ventricular function in patients with severe hypothyroidism and myxedema coma using transthoracic echocardiography and speckle-tracking echocardiography.

Multicenter, retrospective cross-sectional study of adults admitted to intensive care units with severe hypothyroidism who underwent transthoracic echocardiography during hospitalization. Left ventricular (LV) systolic and diastolic function and myocardial deformation, assessed by global longitudinal strain (GLS), were analyzed.

One hundred and twelve patients were included (mean age 53.9 ± 13.7 years; 64.3% female). Myxedema coma was present in 33 patients (29.5%), and 13 (11.6%) had severe hypothyroidism with altered mental status without hypothermia or bradycardia. Median admission thyroid-stimulating hormone was 113.9 (41.9-500.0) mIU/L. The mean LV ejection fraction (LVEF) was 53.9 ± 13.7%, LV GLS -13.5 ± 4.2% (reference -24% to -16%), and right ventricular (RV) GLS -17.9 ± 6% (reference -35% to -17%). Reduced LVEF occurred in 37.5% of patients, abnormal LV diastolic function in 66.7%, and impaired LV and RV GLS in 68.2% and 34.0%, respectively. In multivariable models, β-blocker treatment was associated with lower LVEF and worse biventricular GLS; angiotensin-converting enzyme inhibitor/angiotensin receptor blocker treatment with lower LVEF; and calcium channel blocker exposure was associated with improved RV GLS. In-hospital mortality was 4.5% and occurred in patients with preserved LVEF.

Severe hypothyroidism is associated with frequent systolic and diastolic ventricular dysfunction and prevalent impairment of myocardial deformation. Associations between cardiovascular medication exposure and echocardiographic abnormalities likely reflect confounding by indication and underlying clinical phenotype rather than reflecting causal drug effects. Despite substantial myocardial abnormalities, short-term mortality was low.