High-degree Atrioventricular Block May be Associated with Basedow's Disease: A Case Report

It has been reported that hyperthyroidism could be the cause of arrhythmias at the ventricular and supraventricular levels, while conduction disorders are very rarely described. We report through our observation the case of a 45-year-old patient diagnosed with atrioventricular block (AVB) who, after exploration, showed Basedow’s Disease. The patient was put on Carbimazole 40mg divided in two doses, which allowed to observe a complete regression of the AVB at the end of 2 months of treatment by passing by an alternation AVB 2-th degree mobitz 1 to mobitz 2 and a progressive improvement of the thyroid hormones until obtaining euthyroidism. Thyrotoxic myocarditis is the most likely cause of AVB, since in our patient no classical cause of AVB was found and the conductive disorder was evolving in parallel with hyperthyroidism, which allowed us to retain the diagnosis.