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What are the key differences between POTS and IST?

3 doctors weighed in
Dr. Robert Kwok
Pediatrics
2 doctors agree

In brief: Basic differences...

POTS: Abnormally fast sinus rhythm at rest or minimal activity that accelerates beyond expectations and is out of proportion to physiologic necessity, not resulting from an explainable underlying cause.
Diagnosed by exclusion. IST: Condition of orthostatic intolerance leading to abnormal increase in heart rate with change in position. Diagnosed with tilt table.

In brief: Basic differences...

POTS: Abnormally fast sinus rhythm at rest or minimal activity that accelerates beyond expectations and is out of proportion to physiologic necessity, not resulting from an explainable underlying cause.
Diagnosed by exclusion. IST: Condition of orthostatic intolerance leading to abnormal increase in heart rate with change in position. Diagnosed with tilt table.
Dr. Robert Kwok
Dr. Robert Kwok
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Dr. Robert Kwok
Heart rate in POTS: Resting daytime heart rate exceeds 100 beats/min, and average heart rate on 24-h Holter monitor exceeds 90 beats/min. Heart rate in IST: Persistent increase in heart rate by more than 30 beats/min, or absolute pulse of more than 120 beats/min within 10 min of moving from a supine to upright position in the absence of orthostatic hypotension.
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