Sublingual nitroglycerin used in routine tilt testing provokes a cardiac output-mediated vasovagal response

Objectives We set out to determine the effect of sublingual nitroglycerin (NTG), as used during routine tilt testing in patients with unexplained syncope, on hemodynamic characteristics and baroreflex control of heart rate (HR) and systemic vascular resistance (SVR). Background Nitroglycerin is used in tilt testing to elicit a vasovagal response...

Continuous stroke volume monitoring by modelling flow from non-invasive measurement of arterial pressure in humans under orthostatic stress

The relationship between aortic flow and pressure is described by a three-element model of the arterial input impedance, including continuous correction for variations in the diameter and the compliance of the aorta (Modelflow). We computed the aortic flow from arterial pressure by this model, and evaluated whether, under orthostatic stress,...

Cervically induced ocular torsion: Physiological and clinical aspects

Five healthy subjects were submitted to sinusoidal lateral tilt (amplitude 25° at frequency of 0.2Hz) of the whole body, only the head, or only the trunk about a vertical (subject in upright position) and about a horizontal axis (subject in supine position). The ocular torsioation of the neck by manipulating only the trunk had a negligible...

Variability of near-fainting responses in healthy 6-16-year-old subjects

1. Fainting is a common phenomenon in young subjects, but the final events before the actual faint are not well known. The aim of the present study was to study the inter-individual variability of haemodynamic events associated with near-fainting in children and teenagers. 2. Sixty-eight healthy subjects (aged 6-16 years) performed a 70°tilt-up...

Finger arterial versus intrabrachial pressure and continuous cardiac output during head-up tilt testing in healthy subjects

1. The aims of this study were to determine the clinical feasibility of continuous, non-invasive Finapres recordings as a replacement for intrabrachial pressure during a 30 min head-up tilt, and the reliability of continuous cardiac output computation by pulse contour analysis from the finger arterial versus the brachial waveform. 2. In eight...