[Thyroid function in patients with ventricular arrhythmia]

Hyperthyroidism was diagnosed in 4.8% of 21 patients with persistent ventricular arrhythmias (grades 2 to 5 by the Lown-Wolf classification), and latent hypothyroidism was diagnosed in 38.1% of those, using up-to-date radioimmune assays of thyroid hormones and the thyroliberin (TRH) test. It was those conditions that made arrhythmias resistant to antiarrhythmic treatment in most cases. Latent thyroid dysfunction was particularly common in elderly patients with ventricular arrhythmias and aggravated thyroid history or abnormal thyroid scintigraphic findings. Substitution therapy for hypothyroidism was conducive to the disappearance of paroxysms of ventricular tachycardia and the decrease in total number and grades of ventricular extra-systoles in patients with ventricular arrhythmias; moreover, sensitivity to antiarrhythmic agents developed to replace an earlier resistance.