Blood pressure and sympathetic nerve tone relation during hemodialysis may reflect cardiovascular dysfunction.

Background: The blood pressure response to the rapid removal of fluid during hemodialysis is complex and the pathophysiological mechanisms underlying intradialytic hypotension are not clear and sometimes these mechanisms render dialysis difficult to continue.

Purpose: We analyzed the changes in blood pressure and sympathetic nerve tone and attempted to clarify whether the dynamic pattern of this relationship reflects cardiovascular dysfunction.

Methods: The dynamic pattern of sympathetic nerve activity throughout dialysis was analyzed by frequency analysis of RR intervals recorded by 24 hours Holter electrocardiography in 64 patients and 3 minutes ECG every 15 minutes during dialysis in 121 stable end-stage renal failure patients who underwent maintenance hemodialysis.

Attempt of quantitative analysis of visual evaluation for (123)I-BMIPP myocardial scintigraphy images.

We developed a new technique to quantitatively analyze visual evaluation single photon emission computed tomography (SPECT). Short axis tomograms and color scales were computer scanned. The scales were divided into 25 parts; numbers of each hue pixel were scored 0-100%.

Evaluation of carotid atherosclerosis from the perspective of blood flow reflection.

Detection and prevention of atherosclerosis at an early stage is important for its prevention. The aim of this study was to propose a valid and highly reliable index for the evaluation of carotid atherosclerosis or carotid function. Images of carotid Doppler wave profiles were processed using an image processing software, and the relative fluctuation in blood flow was calculated from the luminance in one cardiac cycle.

Effects of daily physical activity level on the degree of sympathetic tone.

Background: Exercise is recommended for the treatment and prevention of cardiac disorders. Relaxation of the sympathetic nervous system has been considered to be one of the therapeutic mechanisms. However, the means by which the level of daily physical activity affects sympathetic activity remains unclear.

Involvement of carotid baroreceptor function in blood pressure control in the chronic phase: effect on 24-hour ambulatory blood pressure.

Background: It is generally thought that the sole function of baroreceptors is for the regulation of rapid blood pressure fluctuations caused by postural changes and other motion. However, recent studies have suggested that baroreceptors may also be involved in blood pressure control in the chronic phase.

Purpose: The study was performed to examine the involvement of carotid baroreceptors in blood pressure control in the chronic phase, through determination of the relationship between 24-hour blood pressure data and carotid baroreceptor function.

Circadian variation of the myocardial ischemic threshold in patients with ischemic heart disease.

Purpose: Circadian variation of the heart rate (HR) at the myocardial ischemic threshold was compared with that of the HR at the sympathetic tone threshold in 16 cases of effort angina pectoris.

Methods: The high (0.15-0.

Evaluation of the severity of dementia using expectation control function.

The results of an animal experiment without anesthesia suggested the presence of expectation control in which sympathetic nerve tone increases at rest immediately before behaviors to prepare for the subsequent behavior. We investigated whether such function is present in humans in their daily living and whether patients with dementia could be differentiated from healthy adults based on this finding. Using a Holter electrocardiograph with an acceleration sensor, electrocardiograms (ECG) and behavioral states were recorded.

The effects of physical activity and autonomic nerve tone on the daily fluctuation of blood pressure.

The effects of daily activity and autonomic nerve tone on the fluctuation of ambulatory blood pressure were studied in hypertensive patients. The autonomic nerve tone was measured by frequency domain analysis of the RR interval. Physical activity was evaluated by a walk count, converted to a walk rate (WR), recorded using a digital Holter ECG fitted with an accelerometer, with simultaneous monitoring of blood pressure (Bp).