Impact of Hypothyroidism on Echocardiographic Characteristics of Patients With Heart Valve Disease: A Single-Center Propensity Score-Based Study

Right heart failure in the setting of thyrotoxic valvulopathy: the pathophysiology of an often neglected diagnosis: a case report

Background

Hyperthyroidism has a significant, well-established impact on the cardiovascular system on both a molecular and circulatory level. The cardiac consequences of thyrotoxicosis are not uncommon, indicated by a 1.2% prevalence of this disorder in the United States. However, our case describes the less widely observed association between thyrotoxicosis and valvulopathy.

Case summary

A 69-year-old Hispanic male presented with a 3-week history of shortness of breath, intermittent chest pain, and lower extremity swelling. Transthoracic echocardiogram revealed a dilated left and right atrium with severe tricuspid regurgitation, moderate mitral regurgitation, malcoaptation of the tricuspid valve leaflets, and a myxomatous mitral valve. In addition, right ventricular systolic function was moderately reduced. A right and left heart catheterization was performed with findings of normal right heart pressures and normal coronary arteries, respectively. To further evaluate the aetiology of the patient’s heart failure, thyroid studies were sent, revealing a thyroid-stimulating hormone value of <0.010 uIU/mL and a free T4 of 1.96 ng/dL. A 4.9 cm lesion was seen on thyroid ultrasound. We concluded that the patient’s heart failure and notable valvular abnormalities were likely as a result of thyrotoxic heart disease. Furosemide and methimazole were initiated while inpatient, and the patient was discharged with close follow-up.

Discussion

We demonstrate a unique case of the possible hemodynamic and cellular effects of thyroid hormone on the development of primary and secondary valve dysfunction. This association is important for clinicians to be aware of, as treatment of its underlying aetiology can lead to improvement in a patient’s cardiac outcomes.

New aspects of endocrine control of atrial fibrillation and possibilities for clinical translation

Hormones are potent endo-, para-, and autocrine endogenous regulators of the function of multiple organs, including the heart. Endocrine dysfunction promotes a number of cardiovascular diseases, including atrial fibrillation (AF). While the heart is a target for endocrine regulation, it is also an active endocrine organ itself, secreting a number of important bioactive hormones that convey significant endocrine effects, but also through para-/autocrine actions, actively participate in cardiac self-regulation. The hormones regulating heart-function work in concert to support myocardial performance. AF is a serious clinical problem associated with increased morbidity and mortality, mainly due to stroke and heart failure. Current therapies for AF remain inadequate. AF is characterized by altered atrial function and structure, including electrical and profibrotic remodelling in the atria and ventricles, which facilitates AF progression and hampers its treatment. Although features of this remodelling are well-established and its mechanisms are partly understood, important pathways pertinent to AF arrhythmogenesis are still unidentified. The discovery of these missing pathways has the potential to lead to therapeutic breakthroughs. Endocrine dysfunction is well-recognized to lead to AF. In this review, we discuss endocrine and cardiocrine signalling systems that directly, or as a consequence of an underlying cardiac pathology, contribute to AF pathogenesis. More specifically, we consider the roles of products from the hypothalamic-pituitary axis, the adrenal glands, adipose tissue, the renin–angiotensin system, atrial cardiomyocytes, and the thyroid gland in controlling atrial electrical and structural properties. The influence of endocrine/paracrine dysfunction on AF risk and mechanisms is evaluated and discussed. We focus on the most recent findings and reflect on the potential of translating them into clinical application.