PubMed Health⌕ Search

Biomedical subjects

Y Teramachi

Publications and source records attributed to Y Teramachi.

At least 19 recordsLinked to original sources
PubMed1993

[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)

Adult↗
PubMed1985

Dipolarity and dipole location during QRS and T waves in normal men estimated from body surface potential distribution.

The dipolarity of the body surface potential distribution and the locus of the main dipole were estimated mathematically at 2 msec intervals in 27 normal men. The nondipolar content showed time-dependent fluctuation during the QRS. It increased sharply at early and later phases of the QRS. The main dipole moved smoothly within the actual cardiac region and was inscribed in a clockwise direction in most cases. The nondipolar content during the ST-T period was smaller and with less fluctuation than that during the QRS. The main dipole during the T wave moved less than 2 cm near the center of the heart. These results indicated that although a fairly large percentage of the body surface potential could be represented by a single moving dipole, the nondipolar content was larger during initial and late phases of the QRS. It was also suggested that the ventricular repolarization process can be better approximated by a single fixed dipole in normal men.

Adult↗
PubMed1982

Moving multiple dipole model for cardiac activity.

A single-dipole model and a two-dipole model have been examined to approximate the electrical activity of heart; positions as well as vector components of these dipoles were estimated from the body surface potential distribution that was measured with 64 electrodes arranged on the chest. The "residue" has been defined as a measure for how much potential component is left that cannot be attributed to the equivalent dipoles. A locus of the vector end of an equivalent dipole in the single-dipole model is very much like ordinary vectorcardiogram (VCG). The residue has a peak in the last half of QRS; this means that the single-dipole approximation is not valid there. Then another dipole is introduced, which is the two-dipole approximation. The residue has been greatly reduced and the peak disappears; the resultant two dipoles move around in the right and left parts of the heart with nearly opposite directions. The moving-two-dipole model for normal subjects describes the cardiac activity in QRS much better than with the moving-single-dipole model.

Electrocardiography↗