HEART RATE AND BLOOD PRESSURE RESPONSES TO ORTHOSTATIC STRESS DURING HEAD-UP TILT TEST

Abstract

Background: Orthostatic intolerance is the development of symptoms during upright posture. Upright posture is the most physiological orthostatic stressor as it imposes stress leading to gravitational pooling of blood in the splanchnic venous reservoir and leg veins. The most commonly used orthostatic stress test device is the Head-up tilt table (HUT). HUT testing reproduces symptoms of orthostatic intolerance in a setting where haemodynamic variables can be assessed. This study examined the cardiovascular response to orthostatic challenge, and the effect of gender on them. Methods: One hundred patients with complaints of orthostatic intolerance underwent HUT testing under quiet environment. The changes of heart rate and artery blood pressure were observed during tilt table tests. Result: Neurally mediated reflex syncope was the most common pattern constituting 65.07% of all the positive responses followed by Postural orthostatic tachycardia syndrome (POTS) which was seen in 25.3% of positive responses. Dysautonomic response was 4.79% and psychogenic response was the least common seen only in one patient. Conclusions: Neually mediated reflex response is the major haemodynamic pattern displayed by patients of orthostatic intolerance during the tilt table tests, but there are still other three abnormal haemodynamic patterns.