Interventional Cardiology

Patent foramen ovale

What is a patent foramen ovale (PFO)?


A Patent Foramen Ovale (PFO) is a small tunnel located in the septum (muscular wall) that separates the receiving chamber of the heart into the left and right sides. This tunnel is important during fetal circulation as it allows blood to take a short-cut through the heart bypassing the non-breathing lungs.

Often the tunnel closes soon after birth but otherwise it can works like a flap valve, only opening during certain conditions when there are pressure changes in the chest and heart chambers. These changes may occur when people strain while having a bowel movement, cough, sneeze or laugh. 

If the pressure is great enough, blood may travel from the right atrium to the left atrium. In the rare event that there happens to be clot or particles in the blood traveling to the right side of the heart, they could potentially cross the PFO, enter the left atrium, and travel out of the heart and to the brain (causing a stroke) or into a coronary artery (causing a heart attack).

Should that occur then the patient can be treated medically with blood thinning medication or the PFO tunnel can be closed non-surgically using implantable umbrella-type devices (watchman's procedure).

Why do I need PFO closure?

A PFO tunnel is common in adulthood occurring one in four people. In most cases it does not provide symptoms or require any form of treatment. Most people grow up and a lead normal life without even knowing they have a PFO.

However there are a number of harmful and life affecting conditions contributed to by a PFO, such stroke in young people where no other cause is found and it may contribute to migraine headaches.

Your doctor may recommend a PFO closure procedure if it is felt it has contributed to neurological symptoms and if you are at risk of further events. In young people who have suffered a stroke, which is a rare event, a PFO is found in 50% suggesting an association. Some common symptoms of stroke are:

  •  weakness or numbness of the face, arm or leg on one side of the body
  • loss of vision or dimming (like a curtain falling) in one or both eyes
  • loss of speech, difficulty taking or understanding what others are saying
  • sudden severe headache with no known cause
  • loss of balance, unstable walking

Patent Foramen Ovale can be detected by transthoracic echocardiogram with a bubble contrast study or a transoesophageal echo. In some cases the patient is asked to cough or perform a Valsalva manoeuvre to increase the pressure in the right atrium which can reveal the presence of a PFO tunnel.