The authors report on a 74-year-old female patient who revealed Adams-Stokes attacks and was supplied by an R-wave triggered external pacemaker. The patient showed intermittent total AV-block. A frequency of 26 beats was observed. Hypothyroidism was recognized as the cause of this disturbance of cardiac rhythm. After treatment with triiodothyronine the bradycardia disappeared and the external pacemaker could be removed. This case is reported for demonstrating a disturbance of the rhythm caused by hypothyroidism and which is successfully treated by temporary pacemaker and specific drug therapy.