Artificial ventilation by electric stimulation of the phrenic nerves has become clinically significant within the past 20 years and, in the world as a whole, approximately 700 patients have been treated with implanted diaphragmatic pacemakers. The two first patients in whom diaphragmatic pacemakers were implanted in Denmark, had sustained accidental fractures of the second cervical vertebra with subsequent high cervical spinal cord lesions with not only tetraplegia but also respiratory arrest. In both patients, diaphragmatic pacemakers were implanted bilaterally and these were employed for 12-14 hours daily while ventilation with a respirator was employed at night. The main indications for diaphragmatic pacing are paralysis of respiration following high cervical spinal traumata and the chronic central hypoventilation syndrome (sleep apnoea of Undine's curse). Diaphragmatic pacing may improve the mode of ventilation and the quality of life for patients with tetraplegia and respiratory insufficiency. On account of the potential technical problems, the risk of complications and the limited number of patients in whom this operation is suitable, implantation of diaphragmatic pacemakers should be concentrated in a few centres and probably only one in Denmark.