Heart murmurs for beginners Part 2: Atrial septal defect, ventricular septal defect & PDA🔥🔥🔥🔥
Summary
TLDRIn this episode of Learn Medicine, Dr. Coleman reviews three types of heart murmurs: ejection systolic murmur in atrial septal defect, pan-systolic murmur in ventricular septal defect, and machinery murmur in patent ductus arteriosus. He explains the cardiac cycle, how turbulent blood flow creates audible murmurs, and the specific characteristics of each murmur. The video also covers the causes, symptoms, and clinical implications of these defects, helping viewers to identify and understand heart murmurs effectively.
Takeaways
- 👨⚕️ Dr. Coleman introduces the episode by reviewing three types of heart murmurs related to specific cardiac conditions.
- 🔍 The first murmur discussed is the ejection systolic murmur with a split S2, associated with atrial septal defect, characterized by turbulent blood flow during systole.
- 📊 The mnemonic 'lub-wooshh-dubba' is provided to help remember the sound of the atrial septal defect murmur.
- 💧 Atrial septal defects allow left-to-right shunting of blood, increasing the volume in the right atrium and ventricle, leading to the murmur.
- 👂 The ejection systolic murmur of atrial septal defect is best heard at the left upper sternal border and may radiate to the back.
- 🔊 The second murmur is the pansystolic murmur found in ventricular septal defect, which occurs throughout systole and is represented by a plateau wave.
- 🧬 Ventricular septal defects are common congenital heart diseases, sometimes associated with genetic factors and conditions like Down syndrome.
- 🚫 The loudness of the pansystolic murmur often masks the S1 and S2 heart sounds, making them difficult to hear.
- 🌀 The final murmur is the machinery murmur in patent ductus arteriosus, a continuous murmur throughout systole and diastole due to abnormal blood flow between the aorta and pulmonary artery.
- ⏳ Patent ductus arteriosus is a fetal structure that may fail to close after birth, leading to a continuous murmur, and is associated with prematurity and maternal infections.
- 📝 The machinery murmur of patent ductus arteriosus is loudest in the left infraclavicular area and may present with a systolic thrill and bounding pulses.
Q & A
What are the three types of heart murmurs discussed in the video?
-The three types of heart murmurs discussed are the ejection systolic murmur with a split S2 found in atrial septal defect, the pan-systolic murmur found in ventricular septal defect, and the machinery murmur found in patent ductus arteriosus.
What is the characteristic sound of an ejection systolic murmur in atrial septal defect?
-The ejection systolic murmur in atrial septal defect is a crescendo-decrescendo murmur, which can be remembered by the phrase 'lub-wooshh-dubba'.
How does the interatrial septum relate to atrial septal defects?
-The interatrial septum is a thin tissue that separates the left and right atria. Atrial septal defects occur in this tissue, allowing abnormal communication between the left and right atria.
What is the significance of the left-to-right shunt in atrial septal defects?
-The left-to-right shunt in atrial septal defects allows an increased volume of blood to enter the right atrium and subsequently the right ventricle, leading to turbulent blood flow and the characteristic murmur.
What are the typical symptoms of atrial septal defects in clinical history?
-Clinical history of atrial septal defects may include asymptomatic cases, dyspnea, faltering growth, and in later life, symptoms may occur by the age of 25 due to increased pulmonary pressures.
What is the visual representation of a pan-systolic murmur found in ventricular septal defects?
-A pan-systolic murmur is visually represented with a plateau wave, indicating that it occurs throughout the entire duration of systole.
How does the interventricular septum relate to ventricular septal defects?
-The interventricular septum is a thin membrane of tissue that separates the left and right ventricles. Ventricular septal defects occur in this septum, allowing abnormal communication between the ventricles.
What is the typical location to hear the murmur of ventricular septal defects?
-The murmur of ventricular septal defects is a pan-systolic murmur that is loudest at the left sternal edge.
What is the fetal structure that, if not closed after birth, can cause a patent ductus arteriosus?
-The ductus arteriosus is a fetal vascular structure that allows blood to bypass the lungs during fetal development. If it remains open after birth, it can cause a patent ductus arteriosus.
What is the characteristic sound of a patent ductus arteriosus?
-A patent ductus arteriosus produces a machinery murmur, which is a low-pitched, continuous burrrring sound throughout systole and diastole.
What are some risk factors for developing a patent ductus arteriosus?
-Risk factors for developing a patent ductus arteriosus include prematurity, maternal rubella infection during pregnancy, and female gender.
Outlines
👨⚕️ Atrial Septal Defect Murmur Overview
In this section, Dr. Coleman introduces the topic of heart murmurs, specifically focusing on three types: the ejection systolic murmur with a split S2 in atrial septal defect, the pan-systolic murmur in ventricular septal defect, and the machinery murmur in patent ductus arteriosus. He explains the concept of turbulent blood flow causing audible vibrations and the importance of understanding cardiac cycle diagrams. The murmur of atrial septal defect is characterized by an ejection systolic murmur and a split S2 heart sound, occurring during systole with a crescendo-decrescendo pattern. The animation provided illustrates the abnormal blood flow between the left and right atria due to the atrial septal defect, which is typically congenital and can lead to various symptoms, including dyspnea, faltering growth, and a potential reversal of the left-to-right shunt known as Eisenmenger's syndrome.
🔍 Ventricular Septal Defect and Its Murmur
This paragraph delves into the anatomy and murmur associated with ventricular septal defects. The interventricular septum separates the left and right ventricles, and a defect in this tissue allows for abnormal communication between them. The murmur is pansystolic, occurring throughout systole, and is represented by a plateau wave. The animation demonstrates how the increased pressure in the left ventricle leads to a left-to-right shunt across the defect, causing turbulent blood flow and the characteristic murmur. Ventricular septal defects are common congenital heart diseases, potentially linked to genetic factors and conditions like Down syndrome. Clinical presentations may vary, with some individuals being asymptomatic, while others may experience dyspnea and failure to thrive.
🚑 Patent Ductus Arteriosus and Its Continuous Murmur
The final paragraph discusses patent ductus arteriosus, a condition where a fetal blood vessel remains open after birth, allowing abnormal communication between the aorta and pulmonary artery. This results in a machinery murmur heard throughout both systole and diastole due to the continuous turbulent blood flow from the aorta to the pulmonary artery. The murmur is best heard in the left infraclavicular area and may be accompanied by a systolic thrill and bounding peripheral pulse. Risk factors for patent ductus arteriosus include prematurity, maternal rubella infection, and female gender. Clinical signs may include shortness of breath, recurrent respiratory infections, and failure to thrive. The video concludes with an invitation for viewers to participate in a self-test and engage with the Learn Medicine community to influence future video topics.
Mindmap
Keywords
💡Heart Murmurs
💡Atrial Septal Defect (ASD)
💡Ejection Systolic Murmur
💡Ventricular Septal Defect (VSD)
💡Pansystolic Murmur
💡Patent Ductus Arteriosus (PDA)
💡Machinery Murmur
💡S2 Heart Sound
💡Left-to-Right Shunt
💡Eisenmenger's Syndrome
💡Ischemic Stroke
Highlights
Introduction to the Learn Medicine show with Dr. Coleman reviewing three types of heart murmurs.
Explanation of the ejection systolic murmur with a split S2 found in atrial septal defect.
Description of the pan-systolic murmur found in ventricular septal defect.
Introduction of the machinery murmur found in patent ductus arteriosus.
Use of a diagram to depict the cardiac cycle and the concept of turbulent blood flow.
Memory aid 'lub-wooshh-dubba' for the murmur of atrial septal defect.
Animation of blood flow in atrial septal defect and the resulting left-to-right shunt.
Discussion on the increased volume of blood in the right ventricle causing a murmur.
Clinical history and symptoms associated with atrial septal defect.
Risk factors for atrial septal defects, including maternal alcohol use and gender.
Importance of checking for atrial septal defect in young people with unexplained strokes.
Characteristics of the pansystolic murmur in ventricular septal defects.
Anatomy of the ventricular septal defect and its impact on blood flow.
Clinical presentation of ventricular septal defects and associated conditions.
Explanation of patent ductus arteriosus as a persistent fetal vascular structure.
Description of the machinery murmur in patent ductus arteriosus and its causes.
Risk factors for patent ductus arteriosus, including prematurity and maternal infections.
Clinical signs of patent ductus arteriosus, such as systolic thrill and bounding pulses.
Invitation to participate in a self-test and vote on topics for future Learn Medicine shows.
Transcripts
[Music]
Hello and welcome back to the Learn Medicine show. My name is Dr. Coleman,
and in this episode, we will review three more heart murmurs. These murmurs include:
* The ejection systolic murmur with a split S2 found in atrial septal defect
* The pan-systolic murmur found in ventricular septal defect
* The machinery murmur found in the patent ductus arteriosus
By now, you should be familiar with our diagram that depicts one movement through the cardiac
cycle. You should also be familiar with the concept that turbulent blood flow produces audible
vibrations, which can be visually represented with these sound wave patterns. If none of this sounds
familiar, please go back and watch the previous video. I'll put a link at the top of the screen.
Okay, so let's start by reviewing the murmur of atrial septal defect. This presents with an
ejection systolic murmur and splitting of the S2 heart sound. This murmur occurs during systole and
is a crescendo-decrescendo murmur. To help commit this murmur to memory, you can use the phrase
"lub-wooshh-dubba." Okay, so let's add in the murmur now so you can appreciate how it sounds.
Okay, so let's take a moment to look at the atrial septal defect and how the murmur occurs.
Here is our diagram of the heart. Let's remove
the pulmonary artery and the aorta to get a closer look at what's going on.
So looking at this diagram, you'll see that the left atrium and the right atrium are separated by
a thin tissue called the interatrial septum. It's here where atrial septal defects occur.
Atrial septal defects effectively allow for an abnormal communication between
the left and the right atria. With this information in mind,
let's add in some blood flow and produce an animation to see what happens with this defect.
It's during diastole where we see most of the action with the atrial septal defect.
You can see here blood flowing from the atria into the ventricles.
But if we remove the aorta and the pulmonary artery,
we can get a closer look at what is happening. Blood pressure in the left side of the heart
is naturally higher than that in the right side of the heart. This produces a pressure gradient
that allows blood to flow from the left atrium into the right atrium.
This is known as a left-to-right shunt. The key point to take away here is that
the left-to-right shunt allows increased volume of blood to enter the right atrium
and subsequently the right ventricle. So let's continue now by adding back
in the aorta and the pulmonary artery. As usual, the S1 heart sound is produced
by closure of the mitral and tricuspid valves. This produces the sound "lub."
Systole then occurs and during this time, the ventricles contract and force blood through
the pulmonary and the aortic valves. It is the increased volume of blood in the right ventricle
being forced through the pulmonary valve that produces turbulent blood flow, resulting in our
crescendo-decrescendo systolic murmur. As systole comes to an end,
the aortic valve closes as normal, producing the first half of the S2 heart sound.
The second half of the S2 heart sound is produced by delayed closure of the pulmonary valve.
This delay occurs again because of the increased volume of blood
flowing out of the right ventricle. So let's watch this process now in an animation.
Atrial septal defects effectively allow for abnormal blood flow between the left and the
right atrium. They are usually congenital and caused by failed closure of the foramen ovale.
Atrial septal defects are more common in females
and also have increased frequency with maternal alcohol use during pregnancy.
In the clinical history, the presentation may be asymptomatic. However, those that
are symptomatic may have dyspnea and faltering growth. In later life, other symptoms may occur
by the age of 25. The left-to-right shunt can reverse due to increased pulmonary pressures
and this produces a syndrome called Eisenmenger's. Atrial septal defect may also present as ischemic
stroke in later life. Here, small blood clots form in the venous system and these
are able to pass from the right to the left side of the heart through the defect.
Once in the arterial circulation, they can go on to the brain to cause strokes. So any young
person that has an unexplained stroke should go on to have a check for atrial septal defect.
The murmur produced in atrial septal defect is an ejection systolic murmur
with splitting of the S2. It is heard loudest in the left upper sternal border
and radiates through to the back of the thorax.
And now let's turn our attention to ventricular septal defects. This presents as a pansystolic
murmur, which essentially means that it occurs throughout the entire duration of systole.
This murmur can be visually represented with a plateau wave. To commit this murmur to memory,
think about a bearing noise that occurs throughout the duration of systole. Let's listen to this now.
Let's take a moment to look at the anatomy of the ventricular septal defect. The left and
right ventricles are separated by a thin membrane of tissue known as the interventricular septum.
It is here where ventricular septal defects occur. This defect allows for
an abnormal communication between the left and the right ventricle.
Let's use an animation now to understand how the murmur occurs. Blood flows from the atria into
the ventricles, and as usual, the tricuspid and mitral valves close. However, due to increased
pressure in the left ventricle compared to the right ventricle, a left-to-right shunt
occurs across the ventricular septal defect. This produces turbulent blood flow, which generates
our pan-systolic murmur. The aortic and pulmonary valves close, and the cycle begins all over again.
It's worth noting that the S1 and S2 heart sounds are difficult to hear
in the context of a pan-systolic murmur, often because the murmur itself is so loud
that it drowns them out. Let's watch the animation now and listen to the murmur.
Let's pause for a moment to learn more about ventricular septal defects.
They effectively form an abnormal communication between the left and right ventricles. Ventricular
septal defects are a common type of congenital heart disease. It occurs due to abnormal
development of the ventricular septum early in fetal development. Genetics also contribute to
the development of ventricular septal defects. The risk is increased in those with a strong
family history and also in conditions such as trisomy 21, otherwise known as Down syndrome.
With ischemic heart disease, particularly with myocardial infarction, reduced blood supply to the
ventricular septum can cause it to break down and rupture, producing a ventricular septal defect.
The clinical history may be asymptomatic, but may include dyspnea and failure to thrive. The murmur
of ventricular septal defect is a pan-systolic murmur that is loudest at the left sternal edge.
Our final murmur in the series is that of patent ductus arteriosus. This is
described as a machinery murmur, and it occurs throughout systole and diastole.
The murmur is represented visually with a plateau wave that runs throughout systole and diastole.
To help commit this one to memory, think about a continuous burrrring sound that runs the whole
length of the cardiac cycle. We'll add in the murmur now so you can appreciate this:
The ductus arteriosus is a fetal vascular structure that allows blood to bypass the
lungs during fetal development. It usually closes 48 hours after birth, but if it remains patent,
then it allows an abnormal communication between the aorta and the pulmonary artery.
The murmur is produced due to the high aortic blood pressure and lower pulmonary pressures,
creating a gradient that allows for a left-to-right shunt,
where blood continuously flows from the aorta into the pulmonary artery. A continuous stream of
turbulent blood flow produces the machinery murmur both through systole and diastole.
While the murmur is being produced, the mitral and tricuspid valves close. The S1 heart sound
is not heard because the murmur is too loud and drowns it out. This is then followed by blood
being pumped into the pulmonary artery and the aorta. At the end of systole,
the pulmonary and the aortic valves close. The S2 heart sound is not heard again because
the murmur is too loud and drowns it out. The murmur continues to rumble throughout diastole.
So, the patent ductus arteriosus is the persistence of a fetal vascular structure
after birth. There is an increased risk of developing this condition with premature
birth, with maternal rubella infection during pregnancy, and with female gender. The history
may present with shortness of breath, recurrent respiratory infections, or failure to thrive.
Patent ductus arteriosus produces a machinery murmur, which is a low-pitched
rumbling burrowing sound that is continuous throughout systole and diastole. It is loudest
in the left infraclavicular area. Other signs you may see on clinical examination
are a systolic thrill, bounding peripheral pulse, and a widened pulse pressure.
And that brings us to the end of our heart murmurs module. Please take a look at the self-test that
I'm posting, where you can test your ability to identify murmurs by answering some simple
questions. Also, don't forget to head over to the YouTube community channel where you'll be able to
vote on the topic for the next Learn Medicine show. I really value your input because I want
to be making videos that are useful for you. And with that said, don't forget to like and
subscribe and share with your friends. Thanks for stopping by, and I'll see you in the next show!
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