Severe acute myocardial infarction treated with hyperbaric oxygen. Report on forty patients.

Forty patients, aged 35-72, who had had an acute myocardial infarct in the preceding 24 hr, and who were seriously ill, were treated in a hyperbaric oxygen bed at 2 atm (atmospheres) absolute for sessions of 2 hr in and 1 hr out for an average period of 4 days. There were thirty-seven survivors after the treatment, giving an immediate mortality of 7·5%, but three of those died later before leaving hospital, giving a total mortality of 15% in seriously ill patients. Pain and dyspnoea were usually improved in the first hyperbaric session, relapsed in air and progressively improved in successive sessions. Arrhythmias, including heart block, showed similar benefit. No case of cardiac arrest occurred while the patients were actually receiving hyperbaric oxygen. There was, in the opinion of the authors, during a period of over 2 years' experience, a consistent pattern of improvement over and above that expected as spontaneous improvement. The hyperbaric oxygen bed is a promising method of treatment for the acute phase of myocardial infarction, and it is simple to use. There will of course always be an irreducible minimum of patients who will die from obstruction of both coronary arteries or other structural lesions such as rupture or emboli.