[Sinus dysfunction in Basedow's disease. A case report]

INTRODUCTION AND EXEGESIS: The authors report a case of sinus node dysfunction that occurred in a 22-year-old patient with Graves' disease and disappeared after thyroidectomy.

CONCLUSION

Bradycardia is uncommon in hyperthyroidism, the sinus node dysfunction would be due to thyrotoxicity-related myocarditis.

[Hyperthyroidism and atrioventricular block. Pathogenic hypothesis. Apropos of a case and review of the literature]

The authors report the case of a 26-year old male patient who had Graves' disease with a first degree atrioventricular block (AVB) and intermittent episodes of a second degree AVB of the Lucciani-Wenckebach type. These disorders of conduction had features characteristic of a nodal block and disappeared after treatment of the hyperthyroidism. The pathogenesis of atrioventricular conduction disorders in hyperthyroidism remains controverted. The authors put forward the following hypothesis: under the influence of thyroid hormones in excessive amounts, the autonomic nervous system would act by reciprocal excitation and exacerbate a patent or latent hypervagotonia which was pre-existent to the hyperthyroidism. This hypothesis needs to be tested by intracardiac electrophysiological studies with atrial stimulation.