Atrial fibrillation - page 3

What are people with Atrial fibrillation at risk for? Acute MI or Pulmonary Embolus?... Read More

  1. Visit  GrnTea profile page
    0
    Having a PFO is not the same thing as having a right-to-left shunt; saying that 25% of the population has a PFO may be true, but it doesn't mean that they all have a right-to-left shunt by any stretch of the imagination, and it certainly doesn't mean that 25% of all strokes are attributable to this.

    It is physiologically impossible for a right-to-left shunt to exist in the presence of PFO unless the right heart pressure exceeds the left heart pressure, as you note. I will grant you that this does occur-- the heart and soul of the Patriots' offensive line, Tedy Bruschi, suffered such a stroke at a young age, had his hitherto-unappreciated PFO repair done, and was back playing by the end of the season, stroke fortunately resolved. He probably exceeded his left sided pressure with a big Valsalva maneuver at the bottom of a pile. If a stroke occurs in an otherwise healthy young person without other risk factors, this is where they look first.

    However, this actually goes to illustrate my point, which is that actual embolic strokes from venous clots are, in fact, rare. Else we would see many more of them in younger people. Sure, we see a few, but ask yourself-- of all the embolic CVAs you saw in your unit in the last year, how many were, say, in people without atrial fibrillation or single ventricle who were under forty? Under fifty? Under sixty? Not too darn many.
  2. Visit  BostonFNP profile page
    0
    Quote from GrnTea
    Having a PFO is not the same thing as having a right-to-left shunt; saying that 25% of the population has a PFO may be true, but it doesn't mean that they all have a right-to-left shunt by any stretch of the imagination, and it certainly doesn't mean that 25% of all strokes are attributable to this.

    It is physiologically impossible for a right-to-left shunt to exist in the presence of PFO unless the right heart pressure exceeds the left heart pressure, as you note. I will grant you that this does occur-- the heart and soul of the Patriots' offensive line, Tedy Bruschi, suffered such a stroke at a young age, had his hitherto-unappreciated PFO repair done, and was back playing by the end of the season, stroke fortunately resolved. He probably exceeded his left sided pressure with a big Valsalva maneuver at the bottom of a pile. If a stroke occurs in an otherwise healthy young person without other risk factors, this is where they look first.

    However, this actually goes to illustrate my point, which is that actual embolic strokes from venous clots are, in fact, rare. Else we would see many more of them in younger people. Sure, we see a few, but ask yourself-- of all the embolic CVAs you saw in your unit in the last year, how many were, say, in people without atrial fibrillation or single ventricle who were under forty? Under fifty? Under sixty? Not too darn many.
    Not to change the subject from afib but I think that CHDs are incredibly interesting topic as more kids with them survive and end up managed in primary care.

    I have a primary care pt that I manage with a know PFO, and we discuss risks quite frequently. The last meta-analysis I read listed PFO associated with ~5% of all embolic strokes. 25% is way off.
  3. Visit  MunoRN profile page
    0
    Quote from GrnTea
    Having a PFO is not the same thing as having a right-to-left shunt;

    It is actually the same thing. PFO is the most common form of right-to-left circulatory shunt (RLS).

    By definition, a diagnosed PFO is a proven right to left shunt. Other than a few studies that determine PFO prevalence by autopsy, the most common method is by echo bubble study. Of course a bubble study finds a PFO only when a right to left shunt is demonstrated. So by definition, of those diagnosed with PFO by echo, ALL of them demonstrated a right to left shunt, and not only in rare circumstances, the bubbles are injected and are only in the right atrium for a few seconds.

    Quote from GrnTea
    saying that 25% of the population has a PFO may be true, but it doesn't mean that they all have a right-to-left shunt by any stretch of the imagination, and it certainly doesn't mean that 25% of all strokes are attributable to this.
    I've read and re-read my post and I have no idea where you got that 25% of strokes are attributable to PFO's.

    Quote from GrnTea
    It is physiologically impossible for a right-to-left shunt to exist in the presence of PFO unless the right heart pressure exceeds the left heart pressure, as you note. I will grant you that this does occur-- the heart and soul of the Patriots' offensive line, Tedy Bruschi, suffered such a stroke at a young age, had his hitherto-unappreciated PFO repair done, and was back playing by the end of the season, stroke fortunately resolved. He probably exceeded his left sided pressure with a big Valsalva maneuver at the bottom of a pile. If a stroke occurs in an otherwise healthy young person without other risk factors, this is where they look first.

    However, this actually goes to illustrate my point, which is that actual embolic strokes from venous clots are, in fact, rare. Else we would see many more of them in younger people. Sure, we see a few, but ask yourself-- of all the embolic CVAs you saw in your unit in the last year, how many were, say, in people without atrial fibrillation or single ventricle who were under forty? Under fifty? Under sixty? Not too darn many.
    Again, when diagnosed by echo, you're only looking to see if a right to left shunt exists in a window of time lasting a few seconds, you're not waiting hours or even minutes for shunting to occur.

    Rare in medical terms is usually described in terms of occurrence per 1000, or 10,000, etc. If PFO's contribute to 5% of strokes, that's hardly rare, that's 1 in 20. The vast majority of strokes occur in patient's over 50, so considering that of all stroke patients (the majority being older) the prevalence of PFO is 60% higher than in the general population, PFO's would appear to play a role even in the older patient population. All of the stroke patients I've seen with a potentially culprit PFO have been over 50 years old.
  4. Visit  GrnTea profile page
    0
    The paper you quote is from Sweden and may have suffered from translation problems. it says, "When septae fail to fuse, how*ever, the PFO is a potential tunnel that can be opened by reversal of the interatrial pressure gradient. PFO is the most common form of right-to-left circulatory shunt (RLS)."


    I think we agree that a PFO is a potential cause of right-to-left shunt, but since many PFOs are discovered incidentally on autopsy for people who have never suffered any sort of CVA, it's a stretch to say a PFO *is* an RLS. It IS the most common finding associated with RLS, but that's different.

    The CVA patients you've seen with a potential culprit PFO are all over 50. Since they have had their PFOs since birth (actually, before birth) (barring exceptional circumstances), it is clear that the mere existence of a PFO does not inevitably cause stroke. But I think we're probably done explaining this now .
  5. Visit  MunoRN profile page
    0
    Quote from GrnTea
    The paper you quote is from Sweden and may have suffered from translation problems. it says, "When septae fail to fuse, how*ever, the PFO is a potential tunnel that can be opened by reversal of the interatrial pressure gradient. PFO is the most common form of right-to-left circulatory shunt (RLS)."


    I think we agree that a PFO is a potential cause of right-to-left shunt, but since many PFOs are discovered incidentally on autopsy for people who have never suffered any sort of CVA, it's a stretch to say a PFO *is* an RLS. It IS the most common finding associated with RLS, but that's different.

    The CVA patients you've seen with a potential culprit PFO are all over 50. Since they have had their PFOs since birth (actually, before birth) (barring exceptional circumstances), it is clear that the mere existence of a PFO does not inevitably cause stroke. But I think we're probably done explaining this now .
    The quote is from Swedish Medical Center in Seattle, Washington, not from Sweden. It was not translated.

    Not every PFO causes a CVA, but it's been well established that the existence of a PFO correlates with a higher risk of CVA which speaks to my original point; CVA's due to venous/R sided emboli are not impossible and occur more often than we often give them credit for due to a misunderstanding of the prevalence of R to L shunting.
  6. Visit  medicmatt44 profile page
    0
    In order to be a professional Registered Nurse, one must develop a scientific knowledge base. Why in the world are nursing students using Wikipedia and google? What happened to textbooks, journals, and databases?
  7. Visit  BostonFNP profile page
    2
    Quote from medicmatt44
    In order to be a professional Registered Nurse, one must develop a scientific knowledge base. Why in the world are nursing students using Wikipedia and google? What happened to textbooks, journals, and databases?
    I cringe to say this, but....

    Provided its well cited (and any RN should be wise enough to check for citations) it's not the worst source.

    And Google Scholar is a great research database.
    GrnTea and Esme12 like this.
  8. Visit  jessie25 profile page
    0
    I think we need to look at the two options and select the BEST answer. In this case MI versus PE...It will definitely be a PE because with a-fib we are mainly concerned with clots from stagnant blood. Yes, the majority of clots occur in the left side and can lead to a stroke but this does not eliminate the fact that they can potentially occur in the right side as well.

    MIs are mainly caused by CAD (atherosclerosis), or any situation that decreases O2 supply to the heart, CMP etc. Like the above answers said, MIs lead to a-fib; as for the response that said PE is a lung issue and not a heart issue it is always important to understand your patho first and foremost; yes PE occur in the lungs but it has everything to do with the circulatory system.
  9. Visit  GrnTea profile page
    0
    Left sided clots can, in fact, go down the coronary arteries and cause myocardial infarct. Not as easy to do, though, if you think of the mechanics of the contracting ventricle, the valve cusps, and the location of the ostia and the resulting hemodynamics.

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