Tetralogy of Fallot (Year of the Zebra)

00:07:10
https://www.youtube.com/watch?v=Tng2WWV7D0E

Summary

TLDRTetralogy of Fallot (ToF) is a congenital heart defect consisting of four main abnormalities: narrowing of the right ventricular outflow tract leading to more effort to pump blood; right ventricular hypertrophy (thickening of the heart muscle); a ventricular septal defect allowing blood to shunt between heart chambers; and an overriding aorta that can misroute blood. These issues lead to decreased oxygenation of blood, resulting in cyanosis, particularly in newborns. Symptoms can include feeding difficulties and tet spells, where sudden drops in oxygen saturation occur. Diagnosis is made via echocardiography, and surgical intervention within the first year of life is common, typically involving patching the septal defect and correcting the outflow tract issues, which improves overall heart function and oxygenation.

Takeaways

  • 🫀 ToF involves four heart abnormalities: stenosis, hypertrophy, VSD, and aortic override.
  • 🔍 Cyanosis occurs due to shunting of deoxygenated blood to systemic circulation.
  • 👶 Symptoms can include feeding difficulties and failure to thrive.
  • 🏥 Diagnosis is typically done through echocardiography.
  • ⏳ Surgical repair in the first year is crucial for improved outcomes.
  • 💔 Tet spells represent acute episodes of decreased blood oxygenation.
  • 🧬 Chromosome 22 deletions may be linked to ToF.
  • 🩺 Post-surgery, right ventricle can return to normal thickness.
  • 🌬️ Management may involve oxygen therapy and calming techniques during episodes.

Timeline

  • 00:00:00 - 00:07:10

    The video explains Tetralogy of Fallot (ToF), a congenital heart condition with four abnormalities: right ventricular outflow tract stenosis, right ventricular hypertrophy, ventricular septal defect, and aortic override of the septal defect. These defects can lead to cyanosis, where deoxygenated blood is shunted from the right to the left side of the heart, reducing oxygenation of the tissues. It is commonly caused by chromosome 22 deletions and can lead to various symptoms including difficulties in feeding and growth. Diagnosis is typically done through echocardiography, often leading to surgery within the first year of life to correct the defects and allow normal blood flow.

Mind Map

Video Q&A

  • What is Tetralogy of Fallot?

    Tetralogy of Fallot (ToF) is a congenital heart defect characterized by four heart abnormalities.

  • What are the four heart abnormalities in ToF?

    The four abnormalities are right ventricular outflow tract stenosis, right ventricular hypertrophy, ventricular septal defect, and aortic override.

  • Why does cyanosis occur in ToF patients?

    Cyanosis occurs due to deoxygenated blood being shunted from the right to left side of the heart, entering the systemic circulation.

  • What are the symptoms of ToF?

    Symptoms include cyanosis, feeding difficulties, failure to gain weight, and clubbing of fingers and toes.

  • How is ToF diagnosed?

    ToF is usually diagnosed through echocardiography.

  • How is ToF treated?

    Tetralogy of Fallot is typically treated with cardiac repair surgery during the first year of life.

  • What is a tet spell?

    A tet spell refers to a hypercyanotic episode where oxygen saturation drops suddenly due to increased oxygen demand.

  • How can tet spells be managed?

    Management includes calming the patient, providing oxygen and IV fluids, and medications to improve pulmonary blood flow.

  • What is the prognosis for ToF patients after surgery?

    After surgery, the issues related to ToF are addressed, allowing the right ventricle to return to normal thickness and ensuring oxygen-rich blood flows to the body.

  • What genetic association is linked to ToF?

    ToF is associated with chromosome 22 deletions and DiGeorge syndrome.

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  • 00:00:00
    foreign
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    heart condition where patients have four
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    heart abnormalities
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    here's the normal heart with upper
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    chambers the left and the right Atria
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    and lower Chambers the left and the
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    right ventricles as well as the aorta
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    and the pulmonary artery
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    okay so now let's go through these four
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    findings in tof one by one
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    the first abnormality is stenosis or
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    narrowing of the right ventricular
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    outflow tract into the pulmonary artery
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    and this could either be narrowing of
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    the valve itself or narrowing of the
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    infundibulum the area right below the
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    valve either way this makes it harder
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    for deoxygenated blood to get to the
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    pulmonary circulation
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    in response and this also happens to be
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    the second feature The myocardium of the
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    right ventricle hypertrophies or gets
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    really thick in order to contract harder
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    and push blood past the stenosis
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    this causes their heart to look boot
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    shaped on an X-ray
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    third features that patients have a
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    large ventricular septal defect this gap
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    between the ventricles that allows
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    shunting of blood between them
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    now in a patient with an isolated
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    ventricular septal defect meaning those
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    that don't have tof oxygenated blood is
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    shunted from the left side to the right
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    side because the pressure on the left is
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    higher than the pressure on the right
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    for patients with tof though the right
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    ventricular outflow obstruction might
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    block the normal blood flow so much that
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    the pressure in the right ventricle has
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    to be really high to get past it well
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    the high right-sided pressure means that
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    the left side of the heart actually
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    becomes the path of least resistance and
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    deoxygenated blood shunts from the right
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    side to the left side
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    the fourth and final feature is that the
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    aorta overrides the ventricular septal
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    defect and this one's super variable
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    sometimes the aorta is way over here is
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    sitting on top of the septal defect and
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    sometimes it's more on the left
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    ventricular side
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    either way if deoxygenated blood is
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    shunted from right to left then it flows
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    over to the left ventricle and
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    immediately out to the body
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    when you think about it the critical
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    feature of these four is the degree of
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    right ventricular outflow obstruction
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    with less obstruction oxygenated blood
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    might be shunted from left to right and
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    get into the pulmonary circulation where
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    it essentially takes another run through
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    the lungs
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    with more obstruction deoxygenated blood
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    is shunted from right to left and enters
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    the systemic circulation and more
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    deoxygenated blood going to the body
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    essentially means less oxygenation of
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    the tissues right
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    in fact shunting can be severe enough to
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    let the oxygen saturation fall below 80
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    percent at which point patient's skin
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    takes on a bluish or purple
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    discoloration called cyanosis
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    tetralogy of flow is actually the most
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    common cause of cyanotic congenital
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    heart defects accounting for about 50 to
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    70 percent as well as about 10 percent
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    of all congenital heart defects in
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    general
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    now it's not quite clear why some babies
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    develop Toof but it's associated with
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    chromosome 22 deletions and degeorge
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    syndrome
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    babies with tof often have cyanosis
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    around their lips and fingernail beds at
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    Birth and can have clubbing of their
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    fingers and toes within a few months
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    on the other hand if a baby doesn't have
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    severe right ventricular outflow
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    obstruction the baby might not be
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    cyanotic
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    nevertheless having any decrease in the
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    normal oxygenation of blood can affect
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    the baby in a lot of ways and those born
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    with tof can have a range of symptoms
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    including feeding difficulty and failure
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    to gain weight and develop normally
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    babies with toef will often experience
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    symptoms in cyanosis in spells which is
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    referred to as tet spells
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    so say the baby's cruising around and
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    therefore increasing their oxygen demand
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    their heart will try to pump more blood
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    leading to a sudden decrease in oxygen
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    saturation which causes them to be
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    cyanotic
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    when this happens they'll squat down to
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    reduce cyanosis why does this help
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    though well squatting down or getting
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    into a knee chest position slightly
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    Kinks the femoral arteries in the legs
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    which increases vascular resistance in
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    the peripheral arteries and therefore
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    increases pressure in the systemic
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    circulation
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    which increases pressure in the left
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    ventricle enough such that the pressure
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    on the left side is now greater than the
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    right side
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    and that shunt temporarily reverses
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    forcing blood to take the paths of the
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    lungs to be oxygenated therefore
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    reducing cyanosis
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    when patients do have a serious
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    hypercyanotic episode or tet spell they
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    can be treated by keeping them calm and
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    giving them oxygen and IV fluids along
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    with medications that are ultimately
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    aimed at improving pulmonary blood flow
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    a diagnosis of tof is usually made with
  • 00:05:22
    echocardiography which can even be done
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    prenatally
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    most patients with tof will have cardiac
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    repair surgery in the first year of life
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    where the ventricular septal defect is
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    closed with a patch and the right
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    ventricular outflow tract is enlarged
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    fixing these two defects resolves
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    problems caused by the other two defects
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    when the right ventricle no longer has
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    to work so hard to pump blood to the
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    lungs it can return to a normal
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    thickness and fixing the ventricular
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    septal defect means that only
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    oxygen-rich blood will flow out of the
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    left ventricle into the aorta
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    all right as a quick recap tetralogy of
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    fellow or tof is a congenital disorder
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    characterized by four heart
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    abnormalities stenosis in the right
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    ventricular outflow tract
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    right ventricular hypertrophy
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    ventricular septal defect and aortic
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    override of septal defect
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    together these can cause cyanosis in the
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    newborn and is diagnosed with
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    echocardiography
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    tetrology of fellow can be corrected
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    using cardiac repair surgery in the
  • 00:06:29
    first year of life
  • 00:06:54
    helping current and future clinicians
  • 00:06:57
    Focus learn retain and Thrive learn more
Tags
  • Tetralogy of Fallot
  • ToF
  • heart defect
  • congenital anomaly
  • cyanosis
  • echocardiography
  • surgery
  • ventricular septal defect
  • right ventricular hypertrophy
  • tet spells