Recurrent acute pulmonary embolism and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism.

Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including atrial fibrillation and atrial flutter. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Elevated D-dimer levels have been reported in acute pulmonary embolism and it has also been reported that right ventricular overload and hypoxia in acute pulmonary embolism may lead to right ventricular myocardium injury reflected by elevated cardiac troponin levels too. We present a case of recurrent pulmonary embolism associated with subclinical hyperthyroidism, in an 81-year-old Italian woman. Also this case focuses attention on the importance of a correct evaluation of subclinical hyperthyroidism.