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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Atrial septal defect and patent foramen ovale

Cardiology · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Escalate

Treat an acute stroke, systemic embolus, severe hypoxaemia or unstable atrial arrhythmia as an emergency; the presence of a PFO must not distract from reperfusion assessment or the search for another embolic source.

Synopsis

Distinguish haemodynamically important atrial septal defects from a usually incidental PFO and route closure decisions through specialist congenital or stroke services.

  • A secundum ASD is a true deficiency of atrial septal tissue; a PFO is a flap-like persistence of fetal communication and usually has no resting shunt.
  • A significant ASD produces right-atrial and right-ventricular volume loading, often with a wide fixed split second heart sound and pulmonary flow murmur.
  • A PFO is common and usually incidental; do not assume causality after stroke until alternative mechanisms have been excluded.
  • TTE is first line for ASD; contrast echocardiography and TOE refine PFO shunt and septal anatomy when results will change management.
  • Close a haemodynamically significant ASD before irreversible pulmonary vascular disease develops; device closure is preferred for suitable secundum anatomy.
  • Do not close an ASD in established Eisenmenger physiology or when pulmonary vascular resistance makes closure unsafe.
  • NHS England commissions selected PFO closure after otherwise unexplained embolic ischaemic stroke in adults around age 60 or younger after multidisciplinary assessment.

Key red flags

Shunt reversal

Cyanosis, clubbing and advanced pulmonary hypertension suggest right-to-left shunting and make routine closure dangerous.

Investigation priorities

01
12-lead ECGFirst step

Identify right-heart effects and atrial arrhythmia.

Management branches

FirstNew atrial-level shunt

Murmur, right-heart dilatation, unexplained hypoxaemia or incidental septal communication.

  1. Confirm anatomy and physiology with expert echocardiography rather than labelling every communication a PFO.
  2. Assess symptoms, oxygen saturation, rhythm, right-heart size, pulmonary pressure and associated anomalous veins or valves.
  3. Refer a true ASD with right-heart volume overload or symptoms to an adult congenital heart disease service.
  4. If pulmonary hypertension is suspected, obtain specialist haemodynamic assessment before any closure decision.
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Apply principles in context and verify current guidance when a decision affects care. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • ESC 2020 adult congenital heart disease guidelineASD assessment, haemodynamics and closure.
  • NHS England PFO closure policyUK commissioning after recurrent-risk embolic stroke.
  • ESC: PFO in cryptogenic strokeCurrent diagnostic and antithrombotic context.
  • NHS England adult congenital heart servicesUK ACHD service scope.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom