Postprandial Orthostatic Tachycardia
Understanding the Condition
- The American Heart Association suggests that orthostatic intolerance, rather than a primary cardiac disorder, explains why echocardiogram, ECGs, and laboratory tests are all normal in patients with postprandial orthostatic tachycardia 1, 2.
- The European Society of Cardiology indicates that blood pooling in the splanchnic circulation during digestion combined with postural changes leads to an exaggerated heart rate increase when standing after eating 1, 2.
Diagnostic Features
- The American College of Cardiology defines orthostatic tachycardia as a sustained heart rate increase of ≥30 bpm within 10 minutes of standing (or ≥40 bpm if you're 12-19 years old) 1, 2.
- A heart rate increase ≥15 bpm upon standing indicates that the autonomic nervous system is functioning appropriately to compensate for the postural change 2, 3.
Pathophysiology
- The European Society of Cardiology explains that postprandial hypotension occurs because digestion requires significant blood flow to the gastrointestinal tract, reducing the blood volume available for maintaining blood pressure when standing 3.
- Larger meals exacerbate this effect, which explains why symptoms are more pronounced after eating more than usual 3.
Management Strategies
- The American Heart Association recommends performing leg crossing, squatting, or arm tensing when symptoms occur upon standing to acutely raise blood pressure and abort symptoms 2, 3, 5.
- Increasing fluid intake to 2-3 liters daily can expand blood volume and improve orthostatic tolerance 3.