Hypertensive stress increases dispersion of repolarization.

Several electrocardiographic indices for repolarization heterogeneity have been proposed previously. The behavior of these indices under two different stressors at the same heart rate (i.e.

Correlated neurocardiologic and fitness changes in athletes interrupting training.

Purpose: We studied nine male Dutch top marathon skaters during a 1-month interruption of their training schedules after their last contest in the winter to investigate a possible decline in baroreflex sensitivity.

Methods: Before and after this period, a maximal exercise test was done, and at days 0, 4, 7, 14, and 28 neurocardiologic measurement sessions--heart rate and noninvasive baroreflex sensitivity, recumbent and tilt--were performed.

Results: Interruption of training resulted in a significant and relevant decrease in the maximal oxygen uptake (from 65.

AV blocking due to asynchronous vagal stimulation in rats.

The parasympathetic nervous system innervates the heart through two cervical vagal branches. The right vagal branch mainly influences the heart rate by the modulation of the rhythmogenesis of the sinoatrial node. The left branch predominantly influences the conduction properties of the atrioventricular (AV) node.

Effects of wave reflection timing on left ventricular mechanics.

Unlabelled: The aim of this study was to evaluate how the timing of the pressure pulse produced by peripheral reflection affects the left ventricle (stroke volume, ventricular work, coronary driving pressure). Ten isolated perfused rabbit hearts were attached to rubber tubes of different lengths (0.5, 0.

Force generation and shift of mass between myosin and actin in skinned striated muscle fibres at low calcium concentrations.

Skinned muscle fibres from the gracilis muscle of the rabbit were used to record small angle X-ray diffraction spectra under various contractile conditions. The intracellular calcium concentration, expressed as pCa, was varied between 8.0 and 5.