心筋梗塞患者の段階歩行労作時における循環動態に関する検討

Hemodynamic Changes in Patients with Myocardial Infarction while Walking up and Down Stairs

要旨

　急性心筋梗塞患者53例，および健常者31例を対象とし，1階から3階までの階段歩行時における血圧，心拍数，PRP，心電図の変化を，1分毎に記録した．階段歩行労作時においては，急性心筋梗塞患者および健常者のいづれにおいても，臥位コントロール値に比べPRPの著しい増大が示されたが，階段を登り終えた直後における収縮期血圧およびPRPの増大は，心筋梗塞患者において有意に軽度であり，この変化はとくに60才以上の高齢患者において顕著であった．また，階段歩行後の臥位での回復過程をみると，健常者では，平均1.2分で負荷前に回復するのに比べ，心筋梗塞患者においては1.9分に遅延し心機能の低下が示唆された．

　階段歩行労作時においては，階段上昇直後のPRP上昇の少ない患者，高齢患者および回復時間が遅延する患者に注目し，十分な観察がなされなければならないと思われる．

Abstract

　Hemodynamic changes while walking up and down stairs were studied in 53 myocardial infarction (MI) patipents in the chronic phase and 31 adults of normal health.

　Electrocardiograms were recorded by a holter monitor and analyzed for arrhythmias and ST segment changes. Heart rate, systolic and dyastolic pressure, and pressure-rate product (PRP) were also measured by auto sphygmomanometer. These were measured at one minute intervals during the following period: resting in bed for 3 minutes in a supine position; walking to a stairway (1 minute); walking up and down 2 flights of stairs taking 30 seconds for each flight (total of 2 minutes) and returning to their bed (1 minute). All subjects then rested until they reached their starting PRP level.

　After walking up and down the stairs, the PRP increased significantly over that measured while the subjects were in a supine position for both the MI patients and those of normal health. However, the rate of increase for the MI patients was lower than that of the normal adults. Also, for MI patients older than 60, increases of the PRP were lower than the increases of the younger patients. This phenomenon may be due to low cardiac function, low cardiac reserve, vascular sclerosis, and the hemodynamical instability of the weak vasomoter reflex.

　In addition, the average recovery time after walking up and down the stairs was 1.9 minutes for MI patients, compared to 1.2 minutes for normal adults. 17% of the patients spent more than 3 minutes recovering, while the recovery times for all normal adults were within 2 minutes.

　We must always be observant of MI patients, both older people and people whose recovery rate is slow, so as not to increase their cardiac burden while they are walking up and down stairs.