Atrial fibrillation and hyperthyroidism: a new look at their relationship and therapy with lidoflazine

Abstract

Summary Various kinds of dysrhythmias are found in association with hyperthyroidism but especially atrial fibrillation. The causal relationship of chronic atrial fibrillation and the endocrine disorder is controversial, as is its therapeutic management. Six patients with this particular combination of disorders were treated with lidoflazine: a new anti-anginal drug with anti-arrhythmic activity. All six patients returned to sinus rhythm on lidoflazine treatment although still hyperthyroid and remained in sinus rhythm during the follow up period ranging from 5 to 14 months. This occurred independently of antithyroid treatment. Some evidence is put forward that dysrhythmias and most commonly chronic atrial fibrillation are triggered off by hyperthyroidism or other disorders but that they are maintained by permanent cardiac damage due to arteriosclerosis, hypertension, coronary heart disease or rheumatic valve disease. Successful chemical cardioversions and maintenance of sinus rhythm can be obtained independent of the thyroid function. Our results confirm the anti-arrhythmic activity of lidoflazine.

Comparison of lidoflazine and quindine in prophylactic treatment of arrhythmias.

“…Among the 206 patients in these six reports the incidence of these problems was 14 per cent. There are other reported series, however, comprising a total of 57 patients without any of the above dangerous complications (De Vil and Bruyneel, 1974;Bruyneel et al, 1975;Lehmann and Hochrein, 1975). Among the numerous reported series of patients receiving quinidine for medical cardioversion the highest reported incidence of syncope is 6-8 per cent among 237 patients (Cramer, 1968).…”