The authors report a case of cardiac arrest occurring in a patient who had just entered the catheter laboratory for coronary angioplasty. Opacification of the left coronary artery revealed a proximal occluding double spasm unrelated to the distal stenoses for which angioplasty had been requested. Resuscitation and antispastic therapy with intracoronary injection of a nitrate derivative resulted in a complete recovery without any sequellae. The role of coronary spasm in sudden death and the value of the ergometrine test in patients with coronary stenosis are discussed.