A patent foramen ovale — PFO — is a small, flap-like opening between the heart's two upper chambers. It is a leftover from life before birth, when it allowed blood to bypass the lungs. In most people it seals shut in infancy; in around 1 in 4 adults, it remains open. For the great majority, a PFO causes no problems at all and never needs treatment.
But in some people — particularly those who have had a stroke or TIA at a young age with no other cause found — a PFO can act as a passage allowing small blood clots to cross from the right side of the heart to the left, and travel to the brain. In carefully selected patients, closing the PFO with a keyhole procedure significantly reduces the risk of another stroke.
Before birth, every baby has an opening — the foramen ovale — between the heart's upper chambers, allowing blood to bypass the lungs, which aren't yet in use. After birth, the two overlapping flaps of tissue normally fuse together within the first months of life.
In about 25% of people, the flaps never fully fuse, leaving a potential tunnel: a patent (open) foramen ovale. It usually stays functionally closed because pressure on the left side of the heart is higher — but with straining, coughing or certain pressure changes, it can open transiently and allow blood to pass directly from the right side to the left, bypassing the lungs' natural filter.
A PFO is not a "hole in the heart" in the sense of a congenital defect requiring repair (that is an ASD — atrial septal defect, a related but distinct condition). A PFO is a normal anatomical variant — important only in specific circumstances.
Stroke and TIA — the main concern. The lungs normally filter small clots from the venous circulation before blood reaches the brain. A PFO can provide a bypass route: a small clot crossing through it can travel to the brain and cause a stroke. This mechanism — paradoxical embolism — is particularly relevant in younger patients (typically under 60) who have had a stroke or TIA with no other cause found despite thorough investigation (a "cryptogenic" stroke). In this group, a PFO is found far more often than chance would predict, and major randomised trials have shown that closing the PFO significantly reduces the risk of recurrent stroke compared with medication alone in appropriately selected patients.
Migraine with aura. PFO is more common in people who have migraine with aura, and some patients report improvement after closure performed for other reasons. However, trials of closure specifically for migraine have not shown consistent enough benefit for it to be a routine indication — I will always give you an honest appraisal of the evidence.
Divers and decompression illness. A PFO allows venous nitrogen bubbles to bypass the lungs, increasing the risk of decompression sickness in scuba divers. Divers with unexplained or recurrent decompression illness warrant PFO assessment, and closure can allow a safe return to diving in selected cases.
Other situations — including low oxygen levels when upright (platypnoea-orthodeoxia) and before certain surgeries — are less common but well recognised.
Found by chance? If your PFO was discovered incidentally on a scan and you have had no stroke or related problem, in most cases no treatment is needed — reassurance is the right outcome, and I will tell you so plainly.
Your first appointment lasts up to 30 minutes and includes:
For stroke patients, I work closely with your neurologist — the decision to close a PFO after stroke is properly a joint cardiology–neurology decision, and I will coordinate this.
Most patients complete their assessment within one to two weeks.
No treatment — the right answer for most incidentally found PFOs. A PFO in someone with no related problem is a normal variant, not a disease.
Medication alone — for some stroke patients, antiplatelet or anticoagulant medication without closure is appropriate, depending on age, the certainty that the PFO was culpable, and overall risk. This is weighed openly in the joint decision.
Keyhole PFO closure — for selected patients, most commonly after a PFO-related stroke or TIA. The procedure:
PFO closure is one of the safest procedures in structural cardiology, with a very low complication rate in experienced hands. The most common issue is a short-lived irregular heartbeat (atrial fibrillation) in a small percentage of patients in the weeks after the procedure, which usually settles.
A PFO raises one essential question — is it relevant to you? Expert assessment gives you a clear answer, and the right treatment if you need it. Contact my practice team to arrange a consultation at one of my London or Essex locations.
Contact Ms Amelia Garner (PA) on 020 3198 9826 or drozandemir.sec@outlook.com to arrange a consultation.