[Investigations on the cardiovascular system at altitudes up to a height of 7,800 meters (author's transl)].

During a Karakorum expedition electrocardiographic investigations were performed. In the basic camp, 4,800 meters above sea level, ECG of test persons were registered in the resting state and after physical exercise. In addition, long-time recordings of heart rate reactions were made during various phases of mounting up to a height of about 7,800 meters. The ascent in extreme altitudes without an artificial oxygen supply did not cause electrocardiographical signs of myocardial hypoxia. Only supraventricular or ventricular ectopic beats could be detected in some instances. During continuous mounting, the heart rate rises to 120-140 beats per minute and reached 150 beats per minute during the last part up to the summit. Resting blood pressure measured in the basic camp over a period of 15 days showed no significant changes.