Chapter 16: Cardiovascular System

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If you look at the trajectory of modern medicine, there is perhaps no single skill that separates the technician from the true clinician quite like the cardiovascular exam.

We live in an era of high -resolution echoes, cardiac MRIs and instant troponins, and it's very, very easy to just rely on the technology.

Yet, Bates' Guide to Physical Examination makes this really compelling argument that the story of the heart, its pressures, its failures, its hitting turbulences, it's often written right on the surface of the chest if you know how to read the braille.

That is the perfect way to frame it.

And frankly, that is why we are here today.

We are diving into Chapter 16 of the 13th edition of Bates.

This isn't just an anatomy lesson, you know.

It is an argument for the continued relevance of the stethoscope, the hand, and the eyes.

We are looking at the cardiovascular system, arguably the engine room of the entire human body.

And it is a dense chapter.

Let's be honest, it is infamous among students for a reason.

You have complex hemodynamics, you have overlapping acoustic windows, and a lot of physics just masquerading as biology.

Yeah, it can be really intimidating at first.

So our mission for this deep dive is to strip that down.

We aren't just going to read the headers or skim the surface.

We are going to look at the why behind every single sound and every impulse.

We want to translate that dense textbook material, the diagrams, the pressure curves, the grading scales, into a clear, logical audio experience.

Exactly.

We are going to deconstruct the mechanical events, the actual valve closures and pressure crossovers that create the sounds you hear.

We are going to map the mediastinum not just as a diagram, but as a 3D structure you have to visualize through the skin.

That's the hard part, the 3D visualization.

It is.

And we are going to tackle the tough stuff.

The splitting of S2, the physiology of the JVP, and the hemodynamics that make squatting such a useful diagnostic maneuver.

All the things that trip people up.

Before we jump in, just a quick note on boundaries.

Our discussion is strictly grounded in the text of Chapter 16.

We aren't bringing in outside theories or advanced fellowship level cardiology that isn't in the book.

We are sticking to the Bates text to give you the most faithful, high -yield interpretation of the material for your level of training.

I am ready.

And honestly, I show your enthusiasm.

The heart is fascinating because it is logical, it's hydraulic, it's plumbing.

Once you understand the pressures and the plumbing, the sounds make perfect sense.

So let's start where the text starts.

Anatomy and physiology.

The foundation.

Surface projections.

Bates asks us to visualize the mediastinum.

It's not just the heart floating in a vacuum, right?

It's packed in there.

Correct.

You have to have x -ray vision.

The mediastinum is described as this connective tissue line compartment right in the center of the thoracic cavity.

It is bordered by the lungs on either side, the sternum in front, and the spine in the back.

And it's a crowded neighborhood.

It is a very crowded neighborhood.

It houses the heart, the great vessels, the aorta, pulmonary artery, vena cavae, plus the esophagus, the trachea, lymph nodes.

It's all in there.

Now here is the trick that usually trips people up.

The heart doesn't sit straight in the chest.

It's not a valentine heart sitting flat.

It is rotated.

So when we look at the front of a patient's chest, we aren't looking at the front of the heart in an anatomical sense.

We are staring almost directly at the right ventricle.

Precisely.

This is such a key point for the examination.

The right ventricle, or RV,

forms this triangular wedge that sits directly behind and just to the left of the sternum.

It is the most anterior structure in the chest.

Its inferior border essentially tracks the junction of the spurnum and the xiphoid process.

So why does that matter clinically?

Why is that detail so important?

Well think about where you put your hand.

If you have a patient with right ventricular hypertrophy, maybe from severe pulmonary hypertension,

you don't feel that impulse way out of the side.

You feel it right there lifting the sternum.

Or you feel it pushing down into the epigastric area.

The anatomy dictates the exam.

What you feel and where you feel it tells you what part of the heart is struggling.

Which is a huge distinction.

Because contrast that with the left ventricle, the LV is the workhorse, right?

The high pressure pump.

But it is tucked away kind of behind the RV, forming that left lateral margin of the heart.

And that anatomy dictates the most important landmark in the entire cardiac exam.

The point of maximal impulse, or PMI.

To PMI.

Because the LV is tapered to this point, the apex, and because it sits at the fifth intercostal space, roughly in the mid clavicular line, it acts like a little hammer.

During systole, the heart actually rotates forward and it just taps the chest wall.

Bates is very specific about the metrics here.

And this is where the deep dive aspect comes.

Details matter.

It's not just where is it.

It's how big is it?

Correct.

In a healthy supine patient, that tap is concentrated.

The diameter of the PMI should be about 1 -2 .5 cm.

So basically the size of a quarter is smaller.

You should be able to cover it with one finger pad.

But here's where it gets really interesting for the learner.

What if it's bigger?

If I put my hand on a patient's chest and that impulse feels diffuse, you know, like it's lifting three or four of my fingers.

That is evidence of left ventricular hypertrophy, or LVH.

You see, when the muscle mass of that ventricle increases, the area of contact with the chest wall increases.

A PMI greater than 2 .5 cm is actually a surprisingly sensitive sign for LVH.

And you'd see that in things like long -standing hypertension.

Long -standing hypertension, aortic stenosis, anything that makes the LV work harder and bulk up like a bodybuilder.

The muscle gets thicker, so the tap gets bigger.

What about displacement?

If the PMI has migrated, if it's shifted way over to the left towards the axillary line.

That changes the differential diagnosis.

If it is displaced lateral to the mid -clavicular line or more than 10 cm in the mid -sternal line, that suggests LVH or more likely ventricular dilatation.

Dilatation.

Okay, so that's different from hypertrophy.

Very different.

The geometry of the ventricle has blown out.

It's gotten bigger and baggier.

This usually happens due to volume overload from heart failure or from damage from a past myocardial infarction.

The heart is physically bigger and floppier, so the apex moves outward and downward.

So a bigger tap means a thicker muscle.

A tap that's moved out to the side means a bigger, weaker chamber.

That's a great way to summarize it.

There is also a note in the text about COPD patients.

We know their lungs were hyperinflated.

How does that change the geography of the exam?

That is a great nuance and a really practical point.

In chronic obstructive pulmonary disease, the lungs are full of trapped air.

Air is a terrible conductor of sound and impulse.

It dampens everything.

It dampens everything.

Plus, the hyperinflated lungs physically push the diaphragm down, and they rotate the heart clockwise.

So the PMI might disappear from the fifth intercostal space entirely.

You can't feel it.

So where do you look?

In these patients, the most prominent impulse might be in the gavifoid or epigastric area, and that impulse usually reflects the right ventricle, which is hypertrophied from the high pressures in the lungs.

Okay, that makes sense.

Let's move up from the ventricles to the great vessels.

We need to visualize the plumbing above the engine.

Right.

So above the heart, you have the pulmonary artery, which comes off the RV and bifurcase pretty quickly.

Then you have the aorta, which is this big curving vessel that comes up from the left ventricle.

It rises to the level of the sternal angle, that bony ridge on your chest, where the manubrium meets the body of the sternum, and then it arches back and down.

And the vena cava.

On the right side, you have the superior and inferior vena cava, bringing all the deoxygenated blood back to the right atrium.

Bates references figures 16 -2 and 16 -3 here, and it highlights that understanding these contours is essential for reading a chest x -ray.

You need to know which bump on the silhouette corresponds to which vessel.

Let's get into the flow itself.

The text diagrams the circulation flow in figures 16 -4.

Can we walk through the path of a single blood cell?

Let's treat it like a journey.

Let's do it.

It's like a roller coaster.

So imagine a deoxygenated red blood cell returning from your legs.

It travels up the inferior vena cava and dumps into the right atrium.

It passes through the front door, the tricuspid valve, into the right ventricle.

The RV is the low -pressure pump.

It gives a gentle squeeze and pushes the blood through the pulmonic valve into the pulmonary artery, then it's off to the lungs to grab oxygen.

It gets oxygenated, turns bright red and comes back.

Right.

It returns via the pulmonary veins into the left atrium.

From there, it passes through the mitral valve into the massive left ventricle.

The powerhouse.

The powerhouse.

The LV gives this huge high -pressure squeeze and pumps that oxygenated blood through the aortic valve into the aorta and out to the rest of the body.

And the whole cycle starts again.

The text groups these valves into two categories based on structure and location.

We have the AV valves and the semilunar valves.

Simple plumbing classification.

The atrioventricular, or AV valves, are the mitral and tricuspid.

They're the ones that sit between the atria and the ventricles.

They have these little strings, cordae tendineae, that hold them in place.

And the semilunar valves.

Those are the aortic and pulmonic.

They're the exit doors.

They are called that because their leaflets look like three little half moons.

And this leads us directly to the sounds we hear.

The text says S1 and S2 arise from valve closure.

But it's not just the valves clapping like hands, is it?

It's a bit more complex.

It's more complex, yeah.

The sound comes from a combination of things.

The valve leaflets snapping shut, the vibration of adjacent cardiac structures, and the sudden deceleration of the column of blood against the closed valve.

But principally, for the sake of timing, we equate the sounds to valve closure.

This transitions us perfectly into the cardiac cycle.

Bates breaks this down into systole and diastole, using Fig.

16 -5.

We need to clearly define these before we get to the physics.

Okay.

Systole is the period of ventricular contraction.

The ventricle squeezes.

Now think about the valves.

For blood to get out of the heart, the outsole valves, aortic and pulmonic, must be open.

Makes sense.

But to prevent blood from going backward into the atria, the inflow valves, mitral and tricuspid, must be closed.

So systole, outflow open, inflow closed,

and diastole.

Diastole is ventricular relaxation.

The ventricle is filling up for the next beat.

So the mitral and tricuspid valves must be open to let blood in from the atria.

And the exit doors.

The aortic and pulmonic valves must be closed to keep the blood that just left from falling back into the heart.

Okay, that's the choreography.

Now let's move into the engine mechanics.

Bates dedicates a massive section, complete with these complex diagrams, Fig.

16 -6 through 16 -12 to the cardiac cycle pressures.

And it all boils down to one concept.

Pressure gradients.

It is a war of pressures.

That's all it is.

Fluids only move from high pressure to low pressure.

And valves only open or close when the pressure on one side overpowers the other.

If you understand this one physical principle, you understand every single sound the heart makes.

So let's freeze frame the heart.

Let's start at the very end of diastole.

The ventricle is full of blood.

It's relaxed.

The mitral valve is open.

What happens next?

The firing gun goes off.

The electrical signal, the ventricular depolarization, spreads.

The muscle cells of the ventricle start to contract.

Suddenly the pressure inside the ventricle creates a massive spike.

And immediately that ventricular pressure is higher than the very low pressure in the atrium above it.

Right.

And what does fluid want to do?

It wants to go from high to low pressure.

So the blood tries to rush back into the atrium, but it catches the leaflets of the mitral valve and slam.

They snap shut.

And that's S1.

That is S1.

The first heart sound, the lub.

It marks the beginning of systole.

But here is the nuance Bates emphasizes.

The aortic valve.

It hasn't opened yet.

The exit door is still closed.

No, it hasn't.

And this is a critical concept called isovolumetric contraction.

Think about it.

The mitral valve is closed.

The engordic valve is closed.

The ventricle is a sealed chamber.

But the muscle is squeezing with incredible force.

So pressure is skyrocketing.

Skyrocketing.

But the volume can't change because the blood has nowhere to go.

It's just building up the energy required to blow open the aortic door.

And that door has a high pressure guard on the other side, right?

The aorta.

Exactly.

The heart has to generate enough pressure to exceed the diastolic pressure in the aorta, which is usually around 80 millimeters of mercury.

The moment the ventricular pressure crosses that line boon, the aortic valve pops open.

Is that opening audible?

Normally, no.

The opening is silent and the blood ejects rapidly out into the aorta.

So we have silence during the ejection.

Then the squeeze finishes.

The ventricle starts to relax and the pressure drops like a stone.

And now the war of pressures completely reverses.

The pressure in the aorta is high, say 120 millimeter each diastolic.

The pressure in the relaxing ventricle is plummeting down towards zero.

The column of blood in the aorta tries to wash back down into the ventricle and it catches the aortic leaflets.

Slam.

And that's S2.

That is S2, the dub, the end of systole.

So S1 is the beginning of systole, inflow valves close.

S2 is the end of systole, outflow valves close.

That is the basic lub dub.

But the text mentions some pathologic sounds that can happen in between.

Let's talk about the opening snap.

Normally, as we said, the opening of the mitral valve and diastole is silent.

It just glides But if that valve is tenotic, meaning it's stiff, calcified, and restricted, like in rheumatic heart disease, it creates a noise when it's forced open.

Like a rusty hinge?

Exactly like a rusty hinge.

That is the opening snap, or OS.

It's a high -pitched sound that happens very early in diastole.

And then we have the extra diastolic sounds, S3 and S4.

Bates is very specific about what causes these.

Let's start with S3.

Yes.

S3 occurs during the period of rapid ventricular filling, right after the mitral valve opens.

Imagine pouring water rapidly from a height into a bucket.

If the flow hits the bottom hard, it makes a sound.

S3 is caused by the rapid deceleration of that inflowing blood against the ventricular wall.

Is S3 always a bad sign?

No.

And that's an important distinction.

In children and young adults, the ventricle is very supple and compliant, and in S3 it can be a normal physiologic finding.

But in older adults, it is termed an S3 gallop, and usually indicates pathology.

What kind of pathology?

Specifically, heart failure or volume overload.

The ventricle is overfilled and has lost its compliance, and that rapid filling creates this low -pitched thud.

It sounds like Kentucky.

And S4, how is that different?

S4 is different in its timing and its cause.

It happens late in diastole, right before S1.

It marks atrial contraction, the atrial kick.

It happens when the atria squeeze that last bit of blood into a stiff, non -compliant ventricle.

So the ventricle wall is hard.

It's hard, maybe from long -standing hypertension or scar tissue from a prior MI.

And the blood hitting that stiff wall creates a sound.

It sounds like 10SE.

Bates notes that S4 is almost never normal in adults.

It indicates ventricular stiffness.

Okay, we've covered the main sounds, but Bates throws a curveball, splitting.

Specifically, the splitting of S2.

This is one of the hardest things for learners to hear and understand.

Why does S2 sometimes split into two sounds?

This brings us back to the anatomy.

We have a left side and a right side of the heart, and they're not perfectly synchronized.

The left ventricle is stronger and faster.

The right ventricle is a lower pressure system.

Events on the right side of the heart usually occur slightly later than the left, because right -sided pressures are lower.

So the aortic valve closes, and then a split second later, the pulmonic valve closes.

Exactly.

S2 is actually made of two components.

A2, aortic closure, and P2, pulmonic closure.

Normally, they are so close in time that your ear fuses them into one distinct dub.

But consider what happens during inspiration when you take a breath in.

The chest expands,

and the pressure inside your chest, the intra -thoracic pressure, drops.

Right.

It creates a vacuum.

It's like pulling back the plunger on a syringe.

That negative pressure sucks more blood from the body into the right atrium and right ventricle.

Increased venous return.

We're increasing the preload on the right side.

Correct.

Now, the right ventricle has more blood to pump out.

It takes a few milliseconds longer to eject that extra volume.

That extra time delays the closure of the pulmonic valve, P2.

Ah, so A2 happens on time, but P2 gets pushed back.

Precisely.

So during inspiration, you hear A2.

Then a split second later, P2.

Sounds like a split S2.

Lub, T -dub.

And during expiration, what happens then?

During expiration, the intra -thoracic pressure goes back up.

The vacuum is gone.

The extra volume is gone.

P2 moves back earlier and fuses with A2.

So you hear single sound again.

Lub -dub.

This is called physiologic splitting, and it's a hallmark of a healthy heart.

Bates gives a clinical tip on how to listen for this.

Where do we need to put the stethoscope to hear this?

This is critical.

P2 is a much softer sound than A2 because pulmonary artery pressures are so much lower than aortic pressures.

So you need to listen where the pulmonary artery is closest to the surface.

The second and third left intercostal spaces right next to the sternum.

That is where you search for splitting.

If you're listening at the apex, you probably won't hear P2 at all.

Okay.

Let's pivot to murmurs.

The text introduces them here before the exam section.

What is the basic definition?

What makes a murmur a murmur?

Murmurs are sounds of longer duration than the short sharp heart sounds S1 and S2.

They are attributed to turbulent blood flow.

Instead of smooth laminar flow, the blood is swirling and chaotic, and that creates noise.

And Bates categorizes the valve problems that cause this into two main buckets, stenosis and regurgitation.

Simple plumbing.

Stenosis is a narrowed valve that obstructs forward flow.

Imagine putting your thumb over a garden hose nozzle.

It creates a high pressure turbulent hissing noise.

That's a stenotic murmur.

Okay, and regurgitation.

Regurgitation or insufficiency is a valve that fails to close fully,

allowing blood to leak backward.

It's like a leaky faucet or a door that won't latch properly.

That backward jet of blood is turbulent.

The text also introduces the anatomy of listening here, figure 1614.

It maps chest wall locations to valves.

We have the aortic, pulmonic, tricuspid, and metral areas, but there's a pretty big caveat with this, right?

Yes, and this is important.

These areas are where the sounds generated by that valve are usually best heard due to the direction of blood flow, but they are not directly over valves themselves, and the sounds overlap significantly.

So just because you hear a murmur at the apex, it's probably mitral but not guaranteed.

Exactly.

You have to integrate location with timing, radiation, and quality to really know what you're hearing.

It's a clue, not a diagnosis.

Before we get to the exam, we have to touch on the conduction system.

The text keeps it brief but foundational.

It's the electrical wiring.

Right.

It traces the electrical pathway.

It starts at the sinus node in the right atrium, the natural pacemaker.

It fires 60 to 100 times a minute.

The impulse travels through the atria to the AV node.

And the AV node has a special job, right?

It does.

It imposes a slight delay.

This delay is crucial because it allows the atria to finish contracting and fill the ventricles before the ventricles get the signal to squeeze.

Then the signal shoots down the bundle of his and out to the ventricular myocardium.

The ECG is just the paper recording of this electrical activity.

Moving to the mechanics.

The heart as a pump.

We have a formula for cardiac output.

A simple but vital formula.

Cardiac output equals heart rate times stroke volume.

It is the total volume of blood the left ventricle pumps out into the aorta in one minute.

In stroke volume, the amount of blood pumped per beat depends on three big terms that confuse students every single year.

Preload, contractility, and afterload.

Let's define them physically.

How does Bates define preload?

Preload is the stretch.

It refers to the load that stretches the cardiac muscle before contraction.

It corresponds to the volume of blood in the ventricle at the end of diastole.

So think of it like a slingshot.

The further you pull it back, the more blood you put in the ventricle, the more potential energy you have for the next contraction.

That's a perfect analogy.

The Frank Starling mechanism.

Inspiration or exercise increases preload, more blood coming back to the heart.

Dehydration or blood loss decreases it.

And contractility.

That is the intrinsic ability of the muscle to shorten when given a load.

It's the strength of the rubber band itself.

Sympathetic stimulation, like adrenaline, increases it.

Oxygen deprivation, like an NMI, decreases it.

And afterload.

This is the tricky one for most people.

Afterload is the resistance.

It is the sum of forces the ventricle must overcome to eject blood.

Think of it as the tone in the aorta and the peripheral arteries.

If your arteries are clamped down due to vasoconstriction, afterload is high.

It's the wall tension the heart has to generate to even open the aortic valve and push blood out.

Exactly.

High blood pressure is the classic example of increased afterload.

The text links these to pathology.

It talks about volume overload versus pressure overload.

Right.

Pathologic increases in preload, like in valvular regurgitation, lead to volume overload.

The heart gets big and dilated, like a stretched out water balloon.

And pressure overload.

Pathologic increases in afterload, like in hypertension or aortic stenosis, lead to pressure overload.

The heart muscle hypertrophies.

It gets thick and muscular to push against that resistance.

Both, if left unchecked, can eventually cause the pump to fail.

Speaking of pressure, let's talk about arterial pulses and blood pressure.

Why don't we use the pulses in the arms or legs to time the heart cycle?

There is a palpable delay.

The pressure wave travels quickly, but it still takes milliseconds to get from the aorta to your radial artery in your wrist.

It's not instantaneous.

So for timing heart sounds, deciding if a murmur is systolic or diastolic, you always want to use the carotid pulse or the apical impulse, which are much closer to the source.

And what determines the blood pressure we measure?

Bates lists four factors.

The stroke volume,

the distensibility or elasticity of the aorta, the peripheral vascular resistance, and the total volume of blood in the arteries.

Changes in any of these will alter your systolic or diastolic numbers.

One specific term mentioned is pulse pressure.

What's that?

That is simply the difference between the systolic and diastolic pressure.

So if your blood pressure is 120 over 80, your pulse pressure is 40.

A very wide pulse pressure like 160 over 60 can be a sign of aortic regurgitation or stiffness of the aorta in aging.

Now, we have to stop here and dedicate some real time to the jugular venous pressure, the JVP.

In my experience, this is the part of the exam that intimidates learners the most.

They look at a neck and just see skin.

It is intimidating, but it's also arguably the most valuable piece of data you have for assessing the right side of the heart.

Think of the right atrium.

It's deep in the chest.

You can't see it or feel it.

But there is a literal column of blood, the internal jugular vein, that runs directly into it with no valves in between.

So it's a manometer.

It's like a clear tube on the side of a boiler that shows you the water level inside.

Exactly.

It is a direct window into the pressure of the right atrium.

If the pressure in the right atrium goes up, the fluid level you see in the neck goes up.

If the heart is pumping efficiently and the atrium is empty, the level stays low.

We are literally using the neck vein as a dipstick for cardiac function.

The problem, of course, is distinguishing that faint venous pulsation from the big, booming carotid artery which is right next to it.

Bates gives us a rigorous checklist in Box 16 -4.

How do we tell them apart?

It's all about the quality of the movement.

The carotid is a high -pressure arterial hose.

It kicks.

It is a single, vigorous outward thrust.

You can feel it easily.

The jugular.

It's a low -pressure ghost.

It's elusive.

Bates uses the word undulating.

It's more of a flicker than a kick.

Yes.

And it usually has a double flicker for every single heartbeat.

That's the key.

If you see flicker, flicker, flicker, flicker, that's the vein.

If you see boom, boom, that's the artery.

What are some other clues?

The JVP changes with respiration.

It drops when you inhale.

It changes with position.

It drops when you sit up.

And you can eliminate it by putting light pressure just above the clavicle.

The carotid doesn't care about any of that.

It just keeps pounding away.

Let's dissect that double flicker.

This brings us to the waveforms in Fig.

16.

But it's just a description of the tide going in and out of the right atrium.

What is the first flicker?

The first upward flicker is the A wave.

A stands for atrial contraction.

At the end of diastole, the right atrium gives a little squeeze to push that last bit of blood into the ventricle.

That squeeze creates a back pressure wave up the neck.

That's your first flicker.

Okay, so A is for atrial kick.

Then the atrium relaxes.

The pressure drops.

That's the X descent.

The vein collapses briefly.

Then, while the ventricle is squeezing during systole, the tricuspid valve is closed.

And the atrium is acting like a passive bucket, filling up with blood from the body.

As it fills, the pressure rises again.

That's the way V for venous filling.

There is your second flicker.

The bucket is full.

The bucket is full.

And finally, at the start of diastole, the tricuspid valve opens, and the bottom falls out of the bucket.

Blood passively dumps into the ventricle.

The pressure in the atrium crashes.

That is the Y descent.

So when you look at the neck, you are seeing the mechanical history of the right heart.

Squeeze, A, fill, dump, Y.

And Bates points out specific pathologies that you can diagnose just by looking at these waves.

Yes.

Huge Canada waves happen when the atrium contracts against a closed tricuspid valve -like incomplete heart block.

It shoots a massive wave up the neck.

Absent A waves tell you there is no coordinated atrial contraction.

That's classic for atrial fibrillation.

And big, prominent waves suggest tricuspid regurgitation.

When the ventricle squeezes, it shoots blood backward into the atrium and up the neck.

Before we leave anatomy, let's touch on changes over the lifespan.

We aren't all the same age.

How does the heart exam change in an older adult?

As we age, the AP diameter of the chest deepens.

This pushes the heart further away from the chest wall, making the PMI harder to find and S2 splitting harder to hear.

Also, the sounds of murmurs change.

Young people often have benign, innocent flow murmurs.

But a cervical systolic murmur, or brute in an older adult, is highly suspicious for atherosclerotic disease.

That sets the stage perfectly.

We know the part, the sounds, and the pressures.

Now the patient walks in.

Let's move to health history.

General approach.

Bates simplifies this into three key questions.

I love this framework.

It's a great framework.

It keeps you focused.

When approaching a patient with a potential cardiac issue, you should ask yourself, one, is the blood supply to the heart adequate?

That's checking for ischemia or angina.

Two, is the electrical system normal?

That's looking for arrhythmias or palpitations.

Three, and is the pump moving blood adequately?

That's checking for signs of heart failure.

Let's review the symptoms, starting with the big one, chest pain.

It's the most common symptom of coronary heart disease.

And your job is to get the details,

yet to differentiate classic angina, that exertional pressure squeezing, radiating to the shoulder or arm, from atypical symptoms like cramping, grinding, or jaw pain.

The text has a specific and really important warning about women here.

This is a crucial point.

Women, especially those over 65,

often do not present with a classic crushing chest pain.

They might report atypical symptoms.

Instead of chest pain, they might have upper back pain, jaw pain, nausea, profound fatigue, or just shortness of breath.

You cannot miss this.

It's not the Hollywood heart attack scene.

And we must always keep the life -threatening diagnoses at the front of our mind.

Always.

Angina, myocardial infarction, of course.

But also, dissecting aortic aneurysm, which classically presents as a severe tearing pain that radiates to the back and pulmonary embolus.

Next symptom, palpitations.

Bates defines this as an unpleasant awareness of the heartbeat.

It could be skipping, racing, fluttering, or pounding.

The history gives you major clues.

If the patient says it feels like their heart is skipping,

it might be premature contractions.

If they describe a rapid, regular rhythm that starts and stops suddenly like a light switch, you should think of an SVT or a supraventricular tachycardia.

Then there is shortness of breath.

We have dyspnea, orthopnea, and PND.

We need to Dispnea is the general term for an uncomfortable awareness of breathing.

Orthopnea is specific.

It is dyspnea that occurs when lying flat.

Gravity causes fluid to redistribute from the legs and abdomen into the lungs.

You quantify it by asking how many pillows do you need to sleep on.

And KND, proxysmal nocturnal dyspnea.

That's when the patient wakes up suddenly, gasping for air, about one to two hours after falling asleep.

They have to sit up or stand up to catch their breath.

It's a very specific sign of left ventricular heart failure.

That's excessive fluid accumulating in the interstitial space.

In heart failure, it's dependent edema, meaning it settles in the lowest body parts due to gravity.

So the feet and ankles if the patient is walking, or the sacrum if they're bedridden.

Ask about tight rings on their fingers or a tight waistband.

Transient loss of consciousness, or fainting.

If it's cardiac in origin, it usually means the heart isn't pumping enough blood to the brain, most often due to an arrhythmia that is either too fast or too slow.

Okay, we have the history.

Now we put hands on the patient.

Physical examination, general approach.

Bates starts with a bit of a philosophical point about technology, which I appreciate.

It acknowledges that bedside skills have unfortunately declined because of the easy access to ultrasounds and other high tech imaging.

But it emphasizes that the exam is still vital for assessing pump integrity.

You are confirming BP and perfusion, checking the IVP, assessing heart size via the PMI, and listening for valve disease.

It's about assessing the patient right in front of you right now.

Let's get into the techniques of examination.

First up, the basics.

Blood pressure and heart rate.

The basics matter so much.

The patient should rest for five minutes before you take it.

Use the correct cuff size.

A cuff that's too small will give you a falsely high reading.

The arm should be at heart level.

And Bates notes that ambulatory BP monitoring is often more reliable than single clinic readings because of the white coat effect.

Now measuring the JVP, we talked about the physiology, not the manometer, but how do we actually examine it?

What is the geometry of the measurement?

Okay, first you need to visualize the oscillation deep in the neck.

Usually you start with the head of the bed at 30 degrees.

Turn the patient's head slightly away from you.

Use tangential lighting to cast a shadow, which makes the flicker more visible.

Find the highest point of oscillation in the internal jugular vein.

Okay, I found the top of the column of blood.

Now what?

Now you need two rulers, or a card and a ruler.

Place one ruler vertically on the sternal angle.

Why the sternal angle specifically?

Because the sternal angle is a fixed bony landmark that remains roughly five centimeters above the center of the right atrium.

Regardless of whether the patient is lying down or sitting up, it's our constant or reference point.

So we measure the vertical distance from that sternal angle up to the top of the pulsation.

Say it's three centimeters.

Then you add five centimeters.

That five is the fixed distance from the sternal angle down to the atrium.

So three plus five equals eight.

The total JVP is eight centimeters of water.

What's the cutoff for abnormal?

What's too high?

If the measurement is more than three centimeters above the sternal angle, meaning more than eight centimeters total, it is considered elevated.

This finding is highly specific for increased left ventricular endiastolic pressure and a low ejection fraction.

It's a strong sign of volume overload and heart failure.

Next up, carotid arteries.

The text has a very specific safety warning here.

Osculate before you palpate.

Always.

Why is that so critical?

If the patient has significant atherosclerotic plaque in their carotid artery, palpating firmly could theoretically dislodge a piece of that plaque, which could travel to the brain and cause a stroke.

So you listen with the bell of your stethoscope for a brute,

a whooshing sound of turbulence first.

Ask the patient to hold their breath so tracheal sounds don't interfere.

Once it's safe, how do we palpate?

You want to palpate the lower third of the neck just inside the sternocleidomastoid muscle and never ever palpate both sides at the same time.

Right.

A piece that can cause syncope.

You might cut off blood to the brain and cause the patient to pass out one side at a time gently.

What are we feeling for?

What are the characteristics?

Amplitude and contour.

A normal pulse has a brisk, smooth upstroke and a more gradual downstroke.

We look for specific findings.

A bounding or water hammer pulse suggests aortic regurgitation.

A delayed and weak upstroke, what's called pulses parvos et tardis, is a classic sign of aortic stenosis.

The valve is tight, so the blood struggles to get out slowly.

And there are two special pulse patterns mentioned.

Pulses alternans and paradoxical pulse.

Pulses alternans is a rhythm that is regular, but the force of the beat alternates strong, weak, strong, weak.

It indicates severe LV failure.

Paradoxical pulse is a significant drop in systolic BP, more than 10 mmHg during inspiration.

You see that in cardiac tamponade or severe obstructive lung disease.

Now we move to the chest itself, the heart exam.

Positioning is critical here.

If you just leave the patient on their back, you will absolutely miss things.

Box 16 -6 lists three essential positions.

Subbine with the head of the bed at 30 degrees.

This is your standard position for the overall exam.

The left lateral decubitus position.

You have the patient roll onto their left side.

This simple maneuver brings the ventricular apex closer to the chest wall.

It is the best way to feel the PMI and to hear low pitch sounds like an S3, an S4 and the rumble of mitral stenosis with the bell.

And number three, sitting up leaning forward with the patient exhaling completely and holding it.

This brings the aortic root and base of the heart forward.

It's the best way to hear the soft high pitched murmur of aortic regurgitation with the diaphragm.

Let's talk inspection and palpation.

We're looking and feeling for heaves and thrills.

A heave or a lift is a sustained rhythmic lift of your fingers.

It suggests the ventricle is enlarged and pushing hard against your hand.

A thrill is a buzzing or vibratory sensation like a cat purring under your fingers.

If you feel a thrill, that murmur is automatically graded as at least a grade four out of six.

And we palpate the PMI at the apex.

We assess its location, its diameter, its amplitude and its duration.

Don't forget to palpate the RV area at the left sternal border and the subsofoid area, especially in COPD patients.

And check the pulsations which could indicate high pressure in those vessels.

Finally, we get to the stethoscope, auscultation, the art, first the tool itself,

diaphragm versus the bell.

What is the physics here?

Why two sides?

The diaphragm is a large flat surface that you press firmly against the skin.

This design is best for filtering out low frequencies and accentuating high pitched sounds like S1, S2, aortic regurgitation, mitral regurgitation and pericardial friction rubs.

And The bell is for low pitched sounds like an S3 and S4 and the diastolic rumble of mitral stenosis.

The key is to apply it very lightly, just enough to make an air seal.

If you press the bell too hard, the skin beneath it stretches taut and acts like a diaphragm and you'll filter out the very low sounds you were trying to hear.

The text outlines six listening areas.

We have the right second interspace, left second, third, fourth, fifth and the apex.

And Bates emphasizes the inching technique.

Don't just jump from spot to spot like you're playing checkers.

Inch your stethoscope along the sternal border.

This helps you track the sounds as they change in intensity and quality.

It prevents you from getting lost and helps your brain process the soundscape of the chest.

Timing is everything.

We've said it before.

How do we know if a sound is systolic or diastolic?

Just by listening.

Use the carotid pulse.

It's your anchor.

Palpate the carotid artery with the fingers of your left hand while you listen with the stethoscope in your right.

The carotid upstroke happens in systole right after S1.

So if the sound or murmur you hear coincides with the pulse, it's systolic.

If it happens after the pulse is passed, it's diastolic.

That is the single most important skill in auscultation.

Okay, the big topic.

Identifying murmurs.

Bates breaks this down methodically.

First, as you said, timing.

Systolic versus diastolic.

Systolic murmurs happen with the pulse between S1 and S2.

Diastolic murmurs happen between S2 and the next S1.

And remember the rule.

Diastolic murmurs are almost always pathologic.

Systolic murmurs can sometimes be innocent.

And we describe the shape of the murmur.

Is it a crescendo getting louder, a decrescendo getting softer?

Is it a crescendo decrescendo, a diamond shape in aortic stenosis?

Or is it a plateau, spaying the same intensity throughout, like in mitral regurgitation?

And grading.

Risa Levine scale.

Let's run through This is the standard language of cardiology.

Okay, grade one is very faint.

Heard only after you've been listening for a while in a quiet room.

Grade two is quiet, but heard immediately upon placing the stethoscope on the chest.

Grade three is moderately loud.

Grade four is loud.

And it's the first grade associated with a palpable thrill.

Grade five is very loud, still has a thrill, and can be heard with the stethoscope just partly off the chest.

And grade six is the loudest, heard with the stethoscope entirely off the chest, not even touching the skin.

That helps visualize the intensity.

We also assess location and radiation.

Right.

Where is it loudest?

And where does the sound go?

The murmur of aortic stenosis is loudest at the right second inner space, and it radiates up to the neck, following the turbulent blood flow up the carotids.

The murmur of metral regurgitation is loudest at the apex, and it radiates out to the axilla, or the armpit.

And finally, pitch and quality.

Is it high, medium, harsh, rumbling, or musical?

Aortic regurgitation is a classic blowing decrescendo.

Metral stenosis is a low -pitched rumbling sound.

Aortic stenosis is harsh.

Let's summarize the specific murmur types Bates highlights, putting it all together.

Okay.

Mid -systolic murmurs, the ones with that diamond shape, usually point to aortic or pulmonic stenosis, or sometimes innocent flow murmurs in young people.

Pan -systolic murmurs, the plateau -shaped ones that last the whole time, point to mitral or tricuspid regurgitation, and for diastolic murmurs.

Aortic regurgitation is an early diastolic, high -pitched, blowing decrescendo.

Metral stenosis is a mid -to -late diastolic, low -pitched rumble.

We're in the homestretch.

This leads us to the grand finale of the exam, the bedside maneuvers.

This is where you can look like a magician.

You have a patient with a murmur, and you aren't sure what it is.

You ask them to stand up or squat down, and the sound changes.

It's dynamic auscultation.

You are altering the patient's plumbing, their hemodynamics, in real time to see how the heart and its murmurs react.

Let's take squatting.

When a patient squats down from a standing position, two massive things happen physiologically.

First, you are compressing the veins in the legs and the abdomen.

Right.

You are squeezing a huge amount of blood back into the heart.

So preload the volume in the ventricle sheets way up.

The tank is suddenly full.

And simultaneously, you are kinking the femoral arteries in the groin, right?

Exactly.

You are increasing the peripheral vascular resistance, which means you are increasing afterload.

It's harder for the heart to pump blood out.

So you have a full tank plus a blocked exit.

This means the left ventricle is maximally distended.

It is stretched, tight, and full of blood.

How does that help us differentiate, say, aortic stenosis from hypertrophic cardiomyopathy or HOCM?

This is the classic board exam question.

It's the classic question for a reason.

In aortic stenosis, you have a fixed tight valve.

If you fill the ventricle with more blood by squatting, you are forcing more fluid through that same tight hole.

The turbulence increases.

The noise gets louder.

More flow, more turbulence, more noise.

So the murmur of aortic stenosis gets louder with squatting.

But HOCM is a totally different beast.

In HOCM, the obstruction is not the valve.

It's caused by a big fat hypertrophied septum inside the ventricle that gets in the way of outflow tract.

When the ventricle is full and stretched tight from squatting, that fat septum is actually pushed away from the outflow tract.

The obstruction physically opens up.

So the flow becomes smoother.

The obstruction lessens.

Correct.

Squatting decreases the murmur of HOCM.

It's one of the only systolic murmurs that get softer when you give the heart more blood.

Then if you have the patient stand up,

suddenly draining the blood away, the ventricle collapses.

The septum gets in the way again, and the murmur roars back to life.

And the Valsalva maneuver.

Straining like you're having a bowel movement.

The Valsalva maneuver during the strain phase acts similarly to standing.

It decreases venous return to the heart.

So it decreases the murmur of aortic stenosis, but it increases the murmur of hypertrophic cardiomyopathy.

Wow.

We have covered a massive amount of ground.

From the basic anatomy of the mediastinum to the physics of the splitting S2, all the way to these elegant bedside squatting maneuvers.

It is a lot.

But if you look at the logic, it all holds together.

Understanding the pressure differences explains the sounds.

Understanding the anatomy explains the location.

And understanding the hemodynamics explains why the maneuvers work.

Exactly.

So for the learner listening to this, start with the anatomy.

Really visualize the heart under the sternum.

Practice timing the sounds with a carotid pulse.

That is your anchor.

It is everything.

And use the proper positions.

Left lateral decubitus and leaning forward.

Or you will absolutely miss the subtle stuff.

And please remember, these skills take practice.

A lot of practice.

Don't get discouraged if you don't hear a split S2 or a grade 1 murmur on day one.

Nobody does.

Follow the steps in the text.

Be systematic and your ears and hands will learn.

That brings us to the end of this deep dive into Bates's chapter 16.

We really hope this audio guide helps you visualize the text and begin to master the cardiovascular exam.

Keep practicing and stay curious.

A warm thank you from the Last Minute Lecture Team.

See you in the next deep dive.

Goodbye.