‘Transient immediate orthostatic hypotension’ is preferable to ‘initial’ orthostatic hypotension

A drop of systemic blood pressure (BP) occurring shortly after individuals move from supine or seated position to upright posture with subsequent prompt spontaneous resolution is a common physiological occurrence in humans. If the induced hypotension is severe, lightheadedness or postural instability leading to falls and injury may occur. By consensus, a transient systolic BP drop >40 mmHg within 15 s of standing is deemed abnormal and has become termed ‘initial orthostatic hypotension’ (initial OH, iOH). However, the term ‘initial OH’ implies that another hypotensive event will follow shortly. In essence, if an OH event is deemed to be ‘initial’, then one might reasonably assume that a subsequent OH event is imminent. However, in the setting of abrupt movement to upright posture, the BP drop is usually solitary and brief (resolution within 15–30 s); thereafter the individual is usually OH symptom-free until they undertake another similar postural change. Currently, there is no single descriptor for a posture change driven, short-lived, spontaneously resolving OH event, without the implication that further hypotension is imminent as is implied by the term ‘initial OH’. In order to foster more accurate nomenclature, we recommend that ‘initial OH’ be retired, and ‘immediate OH’ or transient ‘immediate OH’ be substituted. While ‘immediate’ OH may be imperfect, it conveys an early onset event without implying additional imminent OH. Thus immediate OH or transient immediate are more accurate descriptors of this common transient hypotensive event. The abbreviation, ‘iOH’, remains unchanged.