The Heart as a Hypothyroid Organ: Cardiac Performance in Myxedema Coma

Article Impact Level: HIGH
Data Quality: STRONG
Summary of  The Journal of Clinical Endocrinology & Metabolism https://doi.org/10.1210/clinem/dgag036
Dr. Joaquin Lado-Abeal et al.

Points

Researchers conducted a detailed echocardiographic study of one hundred twelve intensive care patients to evaluate how profound thyroid hormone deficiency impacts cardiac contractility and overall ventricular performance during critical illness.
The study found that seventy percent of patients exhibited impaired myocardial strain while two-thirds showed abnormal diastolic function even in cases where the traditional ejection fraction measurements appeared normal.
Clinical data suggested that the heart remains hormonally deprived during severe illness rather than simply adapting because it maintains active thyroid hormone receptors and transport mechanisms throughout the body.
Despite the high prevalence of significant myocardial abnormalities found in the cohort the short-term hospital mortality rate was relatively low at only four and a half percent for patients.
These findings support the potential for new clinical trials using thyroid hormone replacement therapy to improve cardiac output and treat cardiomyopathy in patients suffering from life-threatening septic shock.

Summary

This study evaluated the impact of profound thyroid hormone deprivation on cardiac performance by examining 112 intensive care unit patients with severe hypothyroidism, including those presenting with myxedema coma. Given that triiodothyronine (T3) levels are deficient in up to 95% of septic shock cases, the research sought to determine if this hormonal state contributes to septic cardiomyopathy. Utilizing detailed echocardiographic analysis, the investigators quantified systolic and diastolic parameters to identify subclinical myocardial performance deficits often missed by conventional hemodynamic monitoring.

The analysis revealed high rates of subclinical cardiac impairment across the cohort. Specifically, more than one-third of participants exhibited reduced left ventricular ejection fraction, while 66.7% showed abnormal diastolic function. Most significantly, 70% of patients demonstrated impaired myocardial strain, which served as a sensitive early indicator of dysfunction even in those with preserved ejection fraction. Despite this widespread prevalence of myocardial deformation and ventricular dysfunction, short-term in-hospital mortality remained low at 4.5%, suggesting a window for therapeutic intervention before irreversible failure occurs.

The findings suggest that the heart remains hormonally deprived rather than adaptive during critical illness, as it retains essential thyroid hormone receptors. Because isolated cardiomyocyte studies indicate that thyroid hormones can enhance contractility within minutes via non-genomic mechanisms, T3 replacement therapy may be a viable strategy to reverse myocardial depression in septic shock. The study provides a clinical foundation for an upcoming trial evaluating hormone replacement as an inotropic support mechanism. Future research will address the logistical hurdles of ICU-based trials to confirm if restoring thyroid homeostasis can mitigate the severity of hormone-mediated cardiac failure.

Link to the article: https://academic.oup.com/jcem/advance-article/doi/10.1210/clinem/dgag036/8444926?login=false

References

Lado-Abeal, J., Munir, I., Al-Zubaidi, K., Mohammed, S., Tadisina, S., Stiewig-Rapp, M. J., Arvandi, A., Whisenant, T., Ginzo-Villamayor, M. J., Tejera-Perez, C., Perez-Castro, P., Fernandez-Rodriguez, E., Guo, A., Surampudi, P., Bhattacharya, R., Xiang, Y. K., Smith, T. W., & Fernandez-Pombo, A. (2026). Heart ventricular function in hospitalized patients with severe hypothyroidism and myxedema coma. The Journal of Clinical Endocrinology & Metabolism, dgag036. https://doi.org/10.1210/clinem/dgag036