Palpitation, dyspnea and cough are the more common symptoms among patients with overt hyperthyroidism in a matched case-control study involving a total of 393 patients in England [
10]. Palpitation generally correlates with new onset atrial fibrillation or atrial tachycardia matched with increased heart contractility. In the presence of CAD, angina may develop as a consequence of imbalance between myocardial O
2 demand and supply. The increased cardiac contractile function of patients with hyperthyroidism makes the development of heart failure unexpected and raises the question of hyperthyroid cardiomyopathy. Patients may occasionally have exertional dyspnea due, at least in part, to the subnormal response to exercise as a result of the inability to increase heart rate maximally or to lower vascular resistances further during, as normally occurs, with exercise. In many cases the overt hyperthyroid state is characterized by a high LVEF at rest with a paradoxical, but significant fall in LVEF during exercise. [
11] Hyperthyroid cardiovascular system is highly stressed at rest and its functional reserve is reduced. [
12,
13]. Congestive heart failure however is very rare and, when present, is generally associated with atrial fibrillation, more advanced age, persistent systolic LV dysfunction. [
1] Our case report describes a very unusual presentation of overt hyperthyroidism because of the presence and the severity of right heart failure with an impressive right ventricle volume overload which made mandatory to perform transoesophageal echo and angio CT examination to exclude the coexistence of ASD or anomalous pulmonary venous return. No signs of LV dysfunction were present. Only a few cases of reversible right heart failure, with or without pulmonary hypertension, have been reported worldwide. Saad et al. [
5] recently described a similar case regarding a young women with Graves-Basedow disease, without history of cardiovascular disease, who complained about palpitation, peripheral edema, weight loss and fever. The chest x-ray and the echocardiogram showed right ventricular dilatation and severe tricuspid regurgitation without pulmonary hypertension. Right ventricular dysfunction disappeared after therapy with propanolol, corticosteroids and diuretics. In our case the most striking feature has been the normalization of the cardiovascular findings after six weeks of tiamazole therapy. The exact reasons for the development of right ventricle volume overload in hyperthyroidism are yet unclear. Cardiovascular manifestations of hyperthyroidism are frequent and sometimes are relevant in the clinical picture. Usually a hyper-dynamic circulatory state hallmarks the disease with low peripheral resistance, increased output, possibly with pulmonary hypertension as a consequence of increased pulmonary flow. A study published by Merce J et al. in 2005 found a high prevalence of pulmonary hypertension in hyperthyroidism, which was corrected after treatment [
3]. However we found a more unusual presentation with normal pulmonary pressure, right chamber dilatation, massive tricuspid regurgitation, ascites and bilateral pleural effusion. Mechanisms more often invoked and at least in part above described, such as increased cardiac output and venous return, high cardiac output-induced endothelial pulmonary injury, may have act in our patient for a time long enough to provoke right ventricle dilatation and functional tricuspid regurgitation in a well known vicious cycle towards right heart failure.