A patient with acromegaly is described with a relatively small eosinophilic adenoma of the hypophysis, the cardiopathy standing out on the foreground of the clinical pictrire, due to which it has for a long time been interpreted as a primary cardiac ailment. The cardiac disorder proceeds with cardiomegaly, conductivity disturbances and left, quickly progressing into complete and resistant to treatment cardiac insufficiency. The problem of the origination of the so called primary cardiac insufficiency is discussed, resulting from the direct effect of STH upon myocardium.