No, an atrial septal aneurysm does not cause POTS
An atrial septal (fossa-oval) aneurysm is not a recognized cause of postural orthostatic tachycardia syndrome. These are distinct cardiac conditions with different pathophysiologic mechanisms and no established causal relationship in the medical literature.
Understanding the Distinction
What POTS Actually Is
POTS is a chronic autonomic disorder requiring both hemodynamic and symptom criteria 1:
- Hemodynamic: Sustained heart rate increase ≥30 bpm (≥40 bpm ages 12-19) within 10 minutes of standing, without orthostatic hypotension
- Symptoms: Predominant orthostatic intolerance symptoms (lightheadedness, palpitations, fatigue, brain fog) that improve with lying down and persist for ≥3 months
Known Pathophysiologic Mechanisms of POTS
The established mechanisms include 2:
- Partial autonomic neuropathy
- Hypovolemia
- Hyperadrenergic state
- Deconditioning
Structural cardiac abnormalities like atrial septal aneurysms are not among these mechanisms.
What Atrial Septal Aneurysms Actually Cause
Atrial septal aneurysms are localized bulging deformities at the fossa ovalis that are typically asymptomatic 3. When complications occur, they include:
- Systemic embolization/cryptogenic stroke (especially when associated with patent foramen ovale) 4
- Arrhythmias
- Possibly migraine headaches
Notably absent from this list: orthostatic intolerance or autonomic dysfunction.
Critical Diagnostic Pitfall to Avoid
If a patient has both an atrial septal aneurysm and symptoms suggesting POTS, these are coincidental findings, not causally related. The Canadian Cardiovascular Society guidelines explicitly state that POTS requires exclusion of structural heart disease that could explain tachycardia 1. However, an atrial septal aneurysm does not cause tachycardia—it's a structural variant that doesn't affect heart rate regulation.
Proper Diagnostic Approach
When evaluating suspected POTS 1:
- Measure supine heart rate and blood pressure after 5 minutes rest
- Measure standing heart rate and blood pressure for up to 10 minutes
- Document orthostatic symptoms during testing
- Rule out conditions that actually cause secondary tachycardia (Table 5 in guidelines): prolonged bedrest, severe hypovolemia, medications (stimulants, α-blockers, excessive β-blockers), thyroid disease, anemia, dehydration 1
Atrial septal aneurysm is not on this exclusion list because it doesn't cause POTS.
The Bottom Line
The presence of an atrial septal aneurysm should not distract from properly diagnosing and treating POTS if the patient meets diagnostic criteria. Conversely, finding an atrial septal aneurysm does not explain orthostatic symptoms—you must look elsewhere for the cause. These conditions may coexist in the same patient but operate through completely independent mechanisms affecting different physiologic systems (structural cardiac anatomy versus autonomic nervous system function).