SummaryWe studied 42 patients with cardiothyrcosis, principally selected from the department of Cardiology. I contained 37 % of the 112 patients with hyperthyroidism. who were admitted into the department of Internal Medicine in a five years period.Successively we paid attention to the age. the cardiac symptomatology and attendant elcctrocardiografic variations, the clinical evolution and the treatwent. The mortality rate amounted to 14,3 %.