The foramen ovale is a small hole in the atrial septum that allows blood to flow between the atria in the fetus prior to birth. This speeds up blood flow to the heart.
Normally, this foramen ovale closes at birth when increased blood pressure on the left side of the heart forces the opening to close. If it does not close, it is called a patent foramen ovale (PFO). This type of defect acts like a flap valve only opening during times when there is increased pressure in the chest. This can occur when people strain to have a bowel movement, cough, or sneeze. If the pressure is high enough, blood can move from the right atrium to the left atrium. If there is a clot or particles in the blood traveling in the right side of the heart, it can cross the PFO, go into the left atrium, and move out of the heart to the brain (causing a stroke) or into a coronary artery (causing a heart attack).
An atrial septal defect is a hole in the wall between the left and right atria of the heart. If the hole is large enough, oxygen rich blood from the left atrium flows into the right atrium. This causes more work for the heart. They are more common in girls than boys. Most ASD’s do not cause any symptoms and can go undetected until adulthood.
Most people do not have any symptoms with a PFO.
About 40% of people who have had an ischemic stroke have no known cause. A PFO is present and associated with an increase in stroke in about 40% of cases.
Migraine headaches are more common in patients with PFO. There may be an improvement in migraine symptoms in patients who have their PFO’s closed, however more studies need to be done to confirm this finding.
By age 50, many people with ASD will have symptoms that cause difficulty with normal daily living such as: shortness of breath, fainting, palpitations, or inability to exercise without becoming very tired. Untreated ASD’s can lead to other medical problems:
- Pulmonary hypertension- high pressures in the pulmonary arteries and found in 50% of untreated adults by the time they reach the age of 40.
- Right-sided heart failure
- Atrial fibrillation or atrial flutter
A patent foramen ovale is fairly common in the general population at about 25% of people. Even though they are fairly common, only a small percentage of these people are at risk for stroke of unknown cause. In people who have had a stroke of unknown cause, the prevalence of PFO increases to 40% of that population. It is especially common in people who have had a stroke under the age of 55.
A PFO can be associated with an atrial septal aneurysm. This is characterized by increased mobility of the atrial septal wall.
How it is Diagnosed:
A patent foramen ovale is found by having an echocardiogram performed. During the procedure, the patient may be asked to cough or perform the Valsalva maneuver to increase pressure in the right atrium. This will increase the flow of blood from the right to left atrium. A transesophageal echocardiogram can also be performed to give a closer, more detailed view of the PFO.
ASD’s are diagnosed through physical exam and echocardioagram, and sometimes transesophageal echocardiogram.
No treatment is necessary for people with PFO if there are no associated problems such as stroke. Those who have had a stroke or transient ischemic attack (TIA) may be placed on some type of blood thinning medicine such as aspirin, plavix (clopidegrel) or coumadin (warfarin) to prevent recurrence of stroke.
Non-surgical treatment: Cardiac implant
For some people, a cardiologist and a neurologist may recommend closure of the PFO. Most often this is done through a percutaneous rather than a surgical procedure. This process is much less invasive which results in a shorter hospital stay and recovery time. The decision to place a closure device is up to a patient’s cardiologist and his/her review of individual cases.
Treatment for atrial septal defects
There are two types of surgical repair:
- Primary closure: the opening is repaired with sutures alone
- Secondary closure: a tissue patch is used to close the opening.
If your ASD is of the appropriate size and in an appropriate location for closure, a percutaneous approach may be appropriate. This would eliminate the need for surgical closure of the defect. Your cardiologist will tell you which repair method is appropriate for you.