Ichiro Hidaka

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RATIONALE Mechanical stress is known to alter the electrophysiological properties of the myocardium and may trigger fatal arrhythmias when an abnormal load is applied to the heart. OBJECTIVE We tested the hypothesis that the structural heterogeneity of the ventricular wall modulates globally applied stretches to create heterogeneous strain distributions(More)
We test whether the complexity of the cardiac interbeat interval time series is simply a consequence of the wide range of scales characterizing human behavior, especially physical activity, by analyzing data taken from healthy adult subjects under three conditions with controls: (i) a "constant routine" protocol where physical activity and postural changes(More)
It has been reported that phytosterol esters reduce cholesterol absorption and lower serum cholesterol concentration. There have been very few studies published on the effect of dose of phytosterol esters less than 1.0 g/day on plasma cholesterol levels in healthy subjects using commonly consumed foods. In this study, we evaluated the effect of 0.45 g/day(More)
We demonstrate experimentally that noise can enhance the homeostatic function in the human blood pressure regulatory system. The results show that the compensatory heart rate response to the weak periodic signal introduced at the venous blood pressure receptor is optimized by adding noise to the arterial blood pressure receptor. We conclude that this(More)
By injecting noise into the carotid sinus baroreceptors, we previously showed that heart rate (HR) responses to weak oscillatory tilt were enhanced via a mechanism known as "stochastic resonance." It remains unclear, however, whether the same responses would be observed when using oscillatory lower body negative pressure (LBNP), which would unload the(More)
We evaluated the respiratory modulation of heart rate, i.e., respiratory sinus arrhythmia (RSA), with respect to respiratory phase derived from an analytic signal from the lung volume curve, during spontaneous breathing and paced breathing with different patterns. The magnitudes and waveforms of RSA in the phase domain were similar regardless of breathing(More)
OBJECTIVES We examined how repolarization and depolarization abnormalities contribute to the development of extrasystoles and subsequent ventricular fibrillation (VF) in a model of the Brugada syndrome. BACKGROUND Repolarization and depolarization abnormalities have been considered to be mechanisms of the coved-type ST-segment elevation(More)