Quiz Answers with Rationale

  1. True or False: PFO is generally symptomatic.
    • False – PFO is typically asymptomatic.  Around 25% of the general population has PFO.  The condition becomes concerning if it causes stroke, or an increased risk for stroke.  PFO does not always need to be closed percutaneously.  If it is discovered that a patient has a PFO after a stroke or along with another medical condition, it is often treated with pharmaceuticals (AHA, 2017). 
  1. What action mimics the symptoms that PFO may present?
    • While primarily asymptomatic, having the patient perform the valsalva maneuver mimics the symptoms of PFO by changing the intrathoracic pressure and allowing communication between the right and left atria (Kim, Kim, Kang, Kim, & Kwon, 2014). 
  1. Which physiologic process failed to occur if the patient has PFO? 
    • The foramen ovale should functionally close after birth once the baby’s lungs expand.  In utero the pulmonary system pressure is higher than that of the systemic system, effectively keeping the hole open.  However, after birth, pulmonary vascular resistance drops significantly and system vascular resistance doubles, changing the pressure differentials in the heart.  This functionally closes the hole, and the septum primum and septum secundum fuse, permanently closing the foramen ovale.  Any time these tissues do not permanently fuse, the foramen ovale will remain open (McCance & Huether, 2019).
  1. True or False: patent foramen ovale is a condition that has both modifiable and nonmodifiable risk factors. 
    • False- PFO is a genetic condition that is not caused by lifestyle modifications such as diet, exercise, smoking, or stress level (McCance & Huether, 2019).
  1. What keeps the foramen ovale open until a fetus is born?
    • The blood flow from the high-pressure right side to the lower-pressure left side keeps the foramen ovale open in a fetus.  At birth, these pressure gradients reverse with the clamping of the placenta causing the left side of the heart to become higher in pressure.  The reversal of pressure gradients should physiologically cause the foramen ovale to snap closed (McCance & Huether, 2019).