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Biomedical subjects

F Kajiya

Publications and source records attributed to F Kajiya.

At least 109 records · Page 6Linked to original sources
PubMed1978

Theoretical analysis of T-wave polarity based on a model of cardiac electrical activity.

The effect of the gradient of transmembrane action potential duration through the ventricular wall on T-wave polarity and QRS-T angle was investigated using a mathematical model of the electrical activity of the heart which incorporates the characteristic electrophysiological properties of the left ventricular wall. Two models, a rectangular solid model and a concave model, were constructed to simulate a part of the left ventricular wall. The ventricular gradient was defined as a linear decrease (beta msec/cm) of the action potential duration from the endocardium to epicardium. The theoretically-obtained relationship between the QRS-T angle and the ventricular gradient revealed that the transmural gradient (beta) was 10--40 msec/cm when the QRS-T angle was within the normal range. The positive T wave was obtained at the observation point which would correspond to the precordial lead when the transmural gradient was more than 30 msec/cm. The amplitude of the simulated T-wave increased with the ventricular gradient. Thus, our mathematical models can provide the quantitative relationship between the transmural ventricular gradient and T-wave polarity and are compatible with further simulation study for various pathological conditions.

Action Potentials↗
PubMed1975

Assessment of biological age by multiple regression analysis.

In order to generate a reference value of aging, estimation of chronological age of healthy subjects was made by multiple regression analysis. It was shown that the estimated ages of hypertensive subjects by the formula used were significantly higher than their chronological ages. It was further observed that parameters representing various ability of movements might yield an alternative regression formula and that the accuracy in age estimation was improved with application of a second-order regression formula.

Accommodation, Ocular↗