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The important role of alpha 1-adrenoceptors in reperfusion ventricular arrhythmia is mentioned in the introduction. However, the present report is concerned with the sinus node. It is speculated that the decreased positive chronotropic action of alpha 1-adrenergic stimulation due to aging may contribute to the development of sick sinus syndrome.
BACKGROUND Approximately 5% of motor vehicle deaths are assumed to be occur because of a cardiac event thought to be triggered by multiple factors. One important factor is an imbalance of sympathetic and parasympathetic nervous activities, which can be measured by analyzing heart rate variability (HRV). Therefore, a system has been developed to make(More)
The nonlinearity of cardiovascular regulation is higher in normal physiology, whereas several diseases are characterized by a reduction in this nonlinearity. Reduced nonlinearity of heart rate regulation is a robust risk factor for high mortality in patients with myocardial infarction. We investigated the changes in linear and nonlinear correlations of(More)
Accentuated sympathetic nerve activity (SNA) is a risk factor for cardiovascular events. In this review, we investigate our working hypothesis that potentiated activity of neurons in the rostral ventrolateral medulla (RVLM) is the primary cause of experimental and essential hypertension. Over the past decade, we have examined how RVLM neurons regulate(More)
T-wave alternans and QT dispersion were compared as predictors of the outcome of electrophysiologic study and arrhythmia-free survival in patients undergoing electrophysiologic evaluation. T-wave alternans was a highly significant predictor of these 2 outcome variables, whereas QT dispersion was not.
BACKGROUND Patients with a reduced nonlinear component of heart rate regulation have a poorer outcome. METHODS AND RESULTS We investigated whether a nonlinear correlation between renal sympathetic nerve activity (RSNA) and blood pressure or renal blood flow is reduced in conscious, spontaneously hypertensive rats (SHR) by comparing them with normotensive(More)
Correlation dimension analysis (CDA) of spontaneous heart rate variability in humans was performed with the use of autonomic blocking agents (propranolol and atropine) and postural change, and was compared with heart rate power spectral analysis (HRPSA). The correlation dimension was increased by the suppression of sympathetic activity and decreased by the(More)
A mutual information (MI) method for assessment of the relationship between hemodynamic variables was proposed and applied to the analysis of heart rate (HR), arterial blood pressure (BP), and renal sympathetic nerve activity (RSNA) in artificial heart-implanted dogs to quantify correlation between these parameters. MI measures the nonlinear as well as(More)
The frequency of ventricular premature beats (VPBs) has been related to the risk of mortality. However, little is known about the temporal pattern of occurrence of VPBs and its relationship to autonomic activity. Hence, we applied a general correlation measure, mutual information, to quantify how VPBs are generated over time. We also used mutual information(More)