Endocrine Abstracts

Introduction: The syndrome of reduced sensitivity to thyroid hormone (SRSTH) due to mutations of thyroid hormone receptor β (TRB) consists of an inappropriate secretion of TSH with elevated levels of thyroid hormones. Cardiovascular manifestations are often the ones that affect patients. Our aim was to evaluate the cardiac and vascular characteristics of patients with SRSTH due to TRB mutations.

Materials and methods: We analysed clinical, electrocardiogram and cardiac ultrasound data of 287 patients, collected in our Reference Centre of Rare Thyroid Diseases. Data was recorded on diagnosis or during the follow-up of patients. When several sets of the same data existed, the last ones were taken into account. For each variable, 65 to 181 patients could be analysed.

Results: Patients are mainly female (59.6%) with an average age of 28.6 years old at the time of diagnosis. Clinical symptoms were represented by elevated blood pressure (30%), tachycardia (45.7%) and palpitations (45.8%). Electrocardiogram abnormalities were present among 43.3% of patients: 20.2% supraventricular arrythmia (flutter or fibrillation), 15.4% sinusal tachycardia, 3.9% conduction abnormalities and other abnormalities (3.8%). Few patients had ischemic history (4.4%) or cardiac failure. Cardiac ultrasound abnormalities were found in 9.1% of patients including 48% of valvular heart disease and 20% of hyperkinesia. Left ventricular ejection fraction was altered in 3.5% of patients. Many patients used cardiac or blood pressure medications: 18.8% used beta blockers for cardiac indications, 7.30% used an antihypertensive medication, and 4.9% had an anti-coagulant therapy. The study of the genotype-phenotype association is ongoing.

Conclusion: Our study is one of the largest on cardiac and vascular characteristics of patients with TRB mutations. We confirm that patients are mainly affected by tachycardia, palpitations and supraventricular arrythmia that require specific treatment. A regular screening of these cardiovascular manifestations is needed.