著者

角田 均

出版者

社団法人日本循環器学会

雑誌

日本循環器学誌 (ISSN:00471828)

巻号頁・発行日

vol.28, no.10, 1964-10

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Many studies have been reported in connection with the Korotkoff Sound, the sounds heard over the brachial artery at the time of blood pressure measurement by cuff method, which correspond to so-called Swan's 5 sounds. I have studied the relationship between this sound and hemodynamics status of systemic arterial circulation. Materials studied are divided into 4 groups, namely, 1) 26 cases of arteriosclerosis with systolic hypertension of more than 150 mmHg, 2) 16 cases of arteriosclerosis with systolic pressure of less than 150 mmHg, 3) 7 cases of juvenile hypertension with systolic pressure of more than 150 mmHg, and 4) 20 healthy medical student volunteers. All studies were done at resting status in supine position and the pressure cuff was placed on the right arm in the usual manner for blood pressure measuring. Crystal microphone head was placed hermetically on the brachial artery distal to the cuff, and thus, Korotkoff Sound was recorded. On the other hand, the pick-up of the condenser microphone was placed on the left brachial artery correspondingly to the crystal micro-phone head in the other side, and the arterial pressure pulse wave was recorded. Simultaneously, 11 lead ECG was also recorded. 7 out of 20 normal controls were given L-noradrenaline intramuscularly after the recording, and the effects of this procedure was studied by repeating the recording 5 minutes later. In accordance with previous observations, the pulse wave conduction velocity was greater in the arteriosclerotic group. The 1st-point sounds of Korotkoff Sound were produced near the peak of the percussion wave in all cases. Both the time duration between the peak of R in ECG and the Korotkoff Sound (R-P time), and between the foot of the upstroke of the percussion wave and the Korotkoff Sound (A-P time) were reversely proportional to the systolic blood pressure, at the pressures corresponding to so-called Swan' 1 and 2 points. R-P and A-P times were about the same in both hypertensive and normotensive groups at the pressures corresponding to the Swans' 3, 4 and 5 points. In 7 normal groups, who were given L-noradrenaline subsequent to the control observation, have shown the tendency to increase the R-P and A-P times 5 minutes after the injection. Thus, as the cuff pressure was lowered and the blood flow increased, the production of the Korotkoff Sound gradually approached the foot of the upstroke of the percussion wave and the peak of R in ECG. From this I can infer that the hemodynamics status of systemic arterial circulation, for example, propagation of percussion wave and ECG, and the production of the Korotkoff Sound are closely related with each other. There arise a time difference for the blood flow to reach the narrowed portion of the artery under the cuff, which can be considered the origin point of the Korotkoff Sound. This is quite easily explained by Bernoulli's theory.