A positive blister test indicates that the patient’s heart has an unclosed foramen ovale or a lesion of the atrial septum. Because the blood from the patient’s heart flows directly from the right atrium to the left atrium and then shoots through the left ventricle to the artery without exchange through the lungs, the emboli in the venous blood may enter the blood vessels in the brain and form a lacunar cerebral infarction; or the patient may have migraine symptoms because of this, so when the patient has a positive foaming test, it is recommended to do a transesophageal cardiac ultrasound again to clarify Therefore, when the patient has a positive foam test, a transesophageal cardiac ultrasound is recommended to clarify whether there are symptoms of ventricular septal foramen ovale or atrial septal defect, which require active treatment, and to prevent the occurrence of migraine and cerebral infarction. Patients can usually take some oral anticoagulants or anti-platelet aggregation drugs, such as aspirin.