[Are coronary patients endangered through arrhythmias in diving?]

In 25 patients suffering from coronary heart disease with myocardial infarction electrocardiograms were registered continuously during diving and under water swimming. The results are compared to findings in the same patients during bicycle ergometry. Submersion under water produced a highly significant bradycardia and an increase of arrhythmias. During under water swimming heart rate increased less than during 50 Watt ergometry and premature beats were very frequent. It is discussed that the diving bradycardia combined with breath holding provokes the accumulation of arrhythmias. After myocardial infarction patients should not submerge the head under water.