To the Editor.— I endorse all of the comments of Reuben Tizes, MD, on the subject of cardiac arrest occurring during venipuncture (240:213, 1978), as I had the misfortune of witnessing one myself recently. The patient was one of our own laboratory technicians who had given blood on several occasions as a control in various studies in our department. He insisted that he give the blood lying on a couch, since he is extremely prone to fainting. While drawing blood he said to me that he was "fainting" and that I should terminate the phlebotomy. I did not withdraw the needle but stopped drawing on the plunger in the hope that the fainting episode would subside in a few seconds and I would be able to resume the procedure. However, as he looked extremely pale, I felt his pulse and detected extreme bradycardia (approximately 20 beats per minute, although an