[Hemodynamic changes in patients with myocardial infarction while walking up and down stairs]

Hemodynamic changes while walking up and down stairs were studied in 53 myocardial infarction (MI) patients 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.(ABSTRACT TRUNCATED AT 250 WORDS)