Clinical autonomic research : official journal of the Clinical Autonomic Research Society
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To evaluate a modified sequence method with delayed time series for baroreflex sensitivity (BRS) estimation during supine position and orthostatism in healthy human beings. ⋯ BRS estimation with sequence method improves with delayed time series, during supine position and orthostatism. Reduced BRS estimation error and recording time from this method could benefit studies with large populations or patients with low tolerance to orthostatism.
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Individuals with spinal cord injury (SCI) have an increased risk of cardiac arrhythmias, particularly during autonomic dysreflexia (acute hypertensive episodes). This may be partly due to impaired autonomic control of the heart after SCI. The interval between the peak and end of the T-wave of the electrocardiograph (ECG) provides an index of transmural dispersion of repolarisation, a factor underlying the development of ventricular arrhythmias. Another ECG-based risk factor for ventricular arrhythmias is variability in the QT segment, the QT variability index (QTVI). Similarly, P-wave variability may be correlated with risk for atrial arrhythmias. We aimed to: (1) determine whether there are abnormalities in these parameters at rest in those with SCI; (2) determine correlations between these ECG parameters and severity of autonomic impairment after SCI. ⋯ The higher T(peak)-T(end) variability, QTVI and P-wave variability in individuals with SCI could be markers of severity of injury to cardiac autonomic (sympathetic) pathways after SCI, and may represent new risk assessment parameters for predisposition to cardiac arrhythmias in this population.