ONE OF THE therapeutically reversible acute complications of recent myocardial infarction is the development of complete heart block. When the heart rate falls below 25 to 30 beats per minute, syncopal or convulsive seizures develop accompanied by the clinical picture of shock. This emergency requires immediate therapy not only for survival, but to prevent cerebral, cardiac, and renal complications resulting from repeated episodes of inadequate circulation. In the above situation we have employed a procedure similar to that described by Dr. C. W. Lillehei1for therapy of heart block complicating surgical repair of ventricular septal defects. The procedure consists of inserting a No. 18 spinal needle into the right ventricular cavity by puncturing the chest wall just medial to the point of maximal impulse and directing the needle superiorly and medially toward the second right costochondral junction. Then a No. 26 stainless steel wire is passed through the needle