Postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) is a chronic disorder in which standing causes an excessive increase in heart rate and often dizziness, weakness, or palpitations.

Orthostatic intolerance: A group of symptoms that occur or worsen while upright and improve when lying down. POTS is one defined form of this broader upright-intolerance pattern.
Orthostatic vital signs: Heart rate and blood pressure measurements taken while lying down and after standing. These measurements document the cardiovascular response used to assess suspected POTS.
POTS diagnostic criteria: Clinical thresholds and exclusions used to identify postural orthostatic tachycardia syndrome. They specify how large and sustained the standing heart-rate increase must be and what alternative causes to consider.
Inappropriate sinus tachycardia: A persistently or disproportionately fast sinus heart rate not explained by an underlying cause. Its tachycardia is not restricted to standing, unlike the defining posture-linked pattern of POTS.
Venous pooling: Accumulation of blood in dependent veins, especially in the legs, when a person stands. Pooling can reduce blood return to the heart and contribute to POTS symptoms.
Tilt table test: A test that monitors cardiovascular responses as a person is tilted from lying to upright. It can reproduce and measure orthostatic changes when bedside standing tests are inconclusive.
Fluid intake: The amount of water and other fluids consumed over time. Clinicians may recommend increased fluid intake to support circulating blood volume in POTS.
Vasovagal syncope: A transient loss of consciousness caused by a reflex drop in blood pressure, often with slowing heart rate. It can cause upright symptoms or fainting, but its characteristic reflex differs from sustained POTS tachycardia.
Baroreflex: A rapid feedback system that adjusts heart rate and blood-vessel tone in response to blood-pressure changes. Its normal response to standing helps maintain blood pressure and circulation.
Heart rate: The number of heart contractions per minute. Its sustained increase after standing is central to POTS diagnostic criteria.

Linked from 7 pages