We investigated the prevalence and clinical importance of cardiovascular abnormalities in patients with hyperthyroidism.

All consecutive patients diagnosed with hyperthyroidism during a period of 24 months were included in the study. Medical history, complete physical examination results, electrocardiographic findings, laboratory determinations, and Doppler echocardiographic findings were obtained for all patients within 24 hours of diagnosis, and after euthyroidism had been achieved. Age- and sex-matched controls also were studied.

Thirty-nine patients (mean [±SD] age, 52 ± 20 years; range, 25 to 86 years; 72% women), and 39 age- and sex-matched controls, were included. Atrial fibrillation was present in 7 patients (18%). Moderate or severe mitral or tricuspid regurgitation, or both, were present in 9 patients (23%) and in only 1 control (3%; P= 0.01). Mean pulmonary arterial systolic pressure was 38 ± 12 mm Hg (range, 17 to 64 mm Hg) in patients and 27 ± 4 mm Hg (range, 19 to 37 mm Hg) in controls (P= 0.001). Sixteen patients (41%) and 1 control (3%) had pulmonary arterial systolic pressure ≥35 mm Hg. Left ventricular systolic dysfunction was detected in 1 patient. After correction of hyperthyroidism, a significant decrease in pulmonary arterial systolic pressure was observed, and the levels became similar to those of controls.

In patients with hyperthyroidism, there is a high prevalence of pulmonary hypertension and atrioventricular valve regurgitation. These abnormalities usually correct after treatment for hyperthyroidism.