"MRI is not a first-line study, but may be diagnosed by visual assessment or computation of signal–time curves in the pulmonary vein and the left atrium 3."
"Patent foramen ovale is the name given to the persistence of the vital fetal channel between the atria, which allows blood to bypass the lungs until birth. With the onset of neonatal respiration, left atrial pressure rises and coapts the walls of the channel. Over the ensuing months, the walls commonly adhere, ensuring permanent closure. At autopsy, up to 34% of adults have probe patency of the PFO, which may never have been clinically significant. Long-term elevation of right atrial pressure increases the patency rate (see carcinoid heart disease above). The width, length and shape of the tunnel show marked individual variation, which can affect patency. The septum primum forms a flap valve at the fossa ovalis, which may be seen on imaging. PFO flow is intermittent, whereas an ASD is permanently open, and is due to the failed overlap of the septum primum and septum secundum."
"Eustachian valve"
"Chiari network"
Expected headings
"Transthoracic echocardiography"
"Patent foramen ovale is an anatomical variant due to persistence of a normal fetal structure rather than a malformation, in contradistinction to atrial septal defects 21. Right-to-left shunting may occur through a patent foramen ovale at times of increased right atrial pressure, such as sneezing, coughing, straining or Valsalva manoeuvre."
"The ultimate diagnosis of patent foramen ovale is at autopsy by testing for probe patency. One study found that 34% of adults had PFO by this measure. Individual variation is marked and affects size, shape and length. The majority do not cause clinical disease."
"circulating serotonin in metastatic carcinoid causes thickening, retraction and immobility of the right heart valves"
"Patent foramen ovale is the name given to the persistence of the vital fetal channel between the atria, which allows blood to bypass the lungs until birth. With the onset of neonatal respiration, left atrial pressure rises and coapts the walls of the channel. Over the ensuing months, the walls commonly adhere, ensuring permanent closure. At autopsy, up to 34% of adults have probe patency of the PFO, which may never have been clinically significant. Long-term elevation of right atrial pressure increases the patency rate (see carcinoid heart disease above). The width, length and shape of the tunnel show marked individual variation, which can affect patency. The septum primum forms a flap valve at the fossa ovalis, which may be seen on imaging. PFO flow is intermittent, whereas an ASD is permanently open, and is due to the failed overlap of the septum primum and septum secundum."
"severe tricuspid regurgitation (TR) causes volume and pressure overload in the right atrium, with an increased incidence of PFO (60%); a right-to-left shunt means that active serotonin can then damage the left heart valves"
"severe TR and pulmonary regurgitation (PR) can also drastically reduce left ventricular preload; PFO closure in this situation can cause circulatory collapse, and this can be assessed by temporary balloon occlusion 28"