Beziehungen zwischen Dynamik und Regulation des Arteriensystems. In: Thauer R, Pleschka K, editors. Das Arterielle System. Heidelberg: Steinkopff; 1974. pp. 41-60. [DOI: 10.1007/978-3-642-85290-9_4]

Studies on the regulation of myocardial blood flow in man. I.: Training effects on blood flow and metabolism of the healthy heart at rest and during standardized heavy exercise

In a comparative study 11 athletes and 11 untrained students were investigated at rest, of these 6 trained and 5 untrained individuals during exercise as well. Myocardial blood flow was measured by the argon method. Myocardial oxygen consumption, myocardial substrate uptake of glucose, lactate, and free fatty acids and cardiac output were determined by the direct Fick principle. Exercise was standardized according to 65% of an individual's maximal oxygen uptake (delta VO2 max). Coronary flow reserve was determined by dipyridamole injections. All measurements were made during hemodynamic and respiratory steady-state conditions with the subject in a supine position. At rest, myocardial blood flow and myocardial oxygen consumption were significantly lower in trained subjects compared to the untrained ones. These differences were more pronounced during heavy exercise. They cannot be explained completely by hemodynamic parameters. - During exercise, myocardial substrate uptake shifted to a predominant lactate uptake of almost 90% of total substrate uptake. Total substrate uptake as well as lactate uptake correlated significantly with myocardial oxygen. - Coronary flow reserve was lower in the trained group. It is concluded that the heart muscle of a trained individual requires less energy at a given work load than in the untrained state.

[The treatment of excessive arterial hypertension by a permanent cardiac pacemaker system: a case report concerning the possibility to influence the disturbed harmonization between the heart and the arterial system (author's transl)]

In a 63 year old female patient with a history of longstanding arterial hypertension the implantation of a permanent cardiac pacemaker system resulted in a drastic reduction of the elevated blood pressure values, allowing to reduce the formerly necessary high dosage of antihypertensive drugs. It can be assumed that in the case presented the insertion of the permanent pacemaker leads to several hemodynamic changes: firstly, the heart rate is elevated slightly, secondly, the course of the ejection of the stroke volume is changed and consequently the contour of the pulse wave. Especially the latter factor may have an influence on various regulating mechanisms of the circulatory system and thereby on the lowering of the arterial blood pressure and the consecutive reduction of the hypertrophy of the left ventricle. Most probably the baroreceptor reflex system may be of additional great importance. In addition the "desynchronization" of the spread of excitation by the cardiac pacer might be assumed to change the action of the heart in the beginning of the ejection phase into a "softer" way of pumping. The alteration of a rather "rigid" pump (during normal excitation) into a "soft" pump (during desynchronized excitation) thus may lead to a lowering of the arterial pressure a) by decreasing the speed of ejection of the stroke volume and b) by improving the matching between the heart and the arterial "Windkessel".