[Study of thyroid function in patients with paroxysmal supraventricular tachycardia]

Twenty-nine patients with paroxysmal supraventricular tachycardias of different origins and clinical pattern were investigated to detect latent thyroid disorders; hyperthyroidism was diagnosed in 2 of those, and hypothyroidism, in 4. Functional thyroid disorders were more common in patients with mitral prolapse and supraventricular tachycardias due to additional conductive pathways (the Wolff-Parkinson-White syndrome) and paroxysmal nodal reciprocal tachycardia, particularly if they were resistant to antiarrhythmic treatment and/or had aggravated thyroid history. It is suggested that thyroid dysfunction is just a triggering factor of arrhythmia since thyrostatic and replacement therapy eliminate paroxysms of tachycardia, while organic pathology of the heart and its conductive network remains unaffected.