Chapter 53: Adult Cardiovascular Problems

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When you buy a house,

an inspector usually looks for like visible cracks in the foundation.

Right.

Yeah.

Or leaky pipes under the sink.

Exactly.

It's a very straightforward visual process, but inspecting the human heart.

Oh, totally different game.

Yeah.

You're dealing with plumbing and electrical grids hidden behind a moving wall.

You can't just, you know, flip a breaker to see what tripped.

Right.

And a single misfiring wire or a blocked pipe can literally bring the whole house down.

You have to deduce what's failing based entirely on, well, the subtle clues the house is giving you.

Which is exactly why we are here.

If you are our nursing student prepping for the NCLE -X, you are in the right place.

Today's deep dive is a special collaboration with the last minute lecture team.

And our mission today is to conquer chapter 53 on cardiovascular problems.

This is from the Saunders comprehensive review for the NCLE -X RN examination, the ninth edition.

Let's pull out the blueprint.

Yeah, let's do it.

And we aren't just going to like throw flash card facts at you.

The NCLE -X doesn't work that way.

We are going to look at the cause and effect of every single condition in this chapter.

Okay.

So starting with the house itself, it has walls, a protective fence, rooms, and doors.

The walls have three layers, right?

You've got the epicardium on the outside, the myocardium in the middle, and the endocardium lining the inside.

Yeah.

And that myocardium is the actual contracting muscle.

It's the heavy lifter of the whole operation.

And surrounding all of that is the protective fence.

Right.

The pericardial sac.

It holds a very specific amount of pericardial fluid, usually about five to 20 milliliters.

Wait, five to 20 milliliters?

That is a tiny amount.

It is.

It's like barely a tablespoon.

Why so little?

Because it's just enough for lubrication.

It cushions the heart as it beats against the surrounding structures.

Oh, I see.

If you get much more fluid than that, you run into a mechanical problem.

The sac doesn't stretch easily, so excess fluid starts crushing the heart inward.

We'll get into that lethal squeeze, it's called tamponade, a little later.

Got it.

Okay, inside the house, you have the four rooms.

The right and left atria on top, the right and left ventricles on the bottom, controlling the flow between those rooms are the four doors.

The valves, you've got your ventricular valves,

the tricuspid and mitral,

and your semilunar valves, the pulmonic and aortic.

Exactly.

And their entire job is just to keep blood flowing in one direction.

But a house doesn't run without electricity, right?

Muscle doesn't just twitch on its own, it needs a spark.

Let's talk about the wiring.

So the main electrical panel is the sinoatrial, or SA node.

It sits up in the right atrium and naturally generates electrical impulses at a rate of 60 to 100 beats per minute.

Okay.

That spark travels down through the muscle, causing a unified contraction.

And that's your normal sinus rhythm.

But what if the SA node fails?

I assume the heart doesn't just instantly stop, right?

We must have backup generators.

We do, thankfully.

If the SA node fails, the atrioventricular, or AV node, catches the slack.

But it's a slower generator.

It only paces at 40 to 60 beats per minute.

And if that one fails?

If that fails, the Purkinje fibers down in the ventricles can initiate an impulse, but they only fire at 20 to 40 beats per minute.

Wait, really?

Can someone actually live with a heart rate of 25 beats a minute?

Barely.

I mean, it's a physiological failsafe.

It won't sustain you for long.

Right.

But it keeps you from dropping dead the second your SA node gives out, you know?

Yeah.

It gives the medical team a brief window to intervene.

Wow.

Okay.

And regulating this whole electrical grid is the autonomic nervous system.

The sympathetic nervous system releases norepinephrine, so that's like hitting the gas pedal, speeding up the heart rate.

Yeah.

And the parasympathetic system releases acetylcholine.

That's hitting the brakes.

Exactly.

And the brain knows when to hit the gas or the brakes because it's getting constant feedback from baroreceptors.

They sense pressure changes in the vessels.

Oh, great.

It also uses hormones like antidiuretic hormone, ADH, and the renin -angiotensin -aldosterone system.

That tells the kidneys to hold onto water or let it go, manipulating blood volume to control blood pressure.

Okay.

So to monitor all this complex plumbing and wiring, we need a dashboard.

The chapter outlines several key cardiac markers we need to draw from the patient's blood.

Let's start with the big ones, the troponins.

Oh, the troponins are your gold standard.

You need to anchor these normal values in your mind for the exam.

Troponin I should be less than 0 .35 nanograms per milliliter, and troponin T should be less than 0 .1.

Those numbers are practically zero.

Because healthy heart muscle does not leak troponin into the blood, it stays inside the cell.

Okay.

So if you see any rise in those numbers, it mechanically means myocardial cells are bursting open and dying.

Oh, wow.

Yeah.

We also use high -sensitivity troponin now, which catches that cell death even earlier.

That makes sense.

The text also mentions CKMB, which peaks around 18 hours after acute ischemia, and myoglobin, which rises fast but isn't strictly specific to the heart.

Right.

But then there's BNP, B -type natriuretic peptide.

I know the textbook rule is that it might be less than 100 picograms per milliliter.

But what actually is it?

Why does it rise?

So think of BNP as the heart's chemical distress flare.

Okay.

When the ventricles are overfilled with fluid and stretching to their absolute limit, the heart tissue releases BNP into the blood.

And where does it go?

That BNP travels to the kidneys and essentially says, hey, we're drowning up here.

Please slush out some sodium and water.

Oh, I see.

That's why a high BNP, anything over 100, means severe heart failure.

The higher the number, the louder the heart is screaming for volume relief.

That makes so much more sense than just memorizing the number 100.

Okay.

Speaking of diagnostics, let's say a patient comes in and we need to look at the physical pipes.

We schedule a cardiac catheterization, which involves injecting an iodine contrast dye into their vessels to see where the blockages are.

Exactly.

But let's say our patient has diabetes and takes metformin.

My instinct as a student might be, okay, they are NPO for the procedure, so just monitor their blood sugar.

But the tech screams that this is a massive NCLEX safety alert.

Oh, a critical red flag.

If they take metformin, it must be withheld for 24 hours before the procedure and for 48 hours after.

Why?

What does a diabetes pill have to do with iodine dye in the heart?

It comes down to how the body clears chemicals.

The iodine contrast dye is heavy on the kidneys.

It can temporarily stun them or reduce their function.

Okay, right.

So if the kidneys slow down and the patient is taking metformin, the kidneys can't filter the metformin out.

It builds up in the bloodstream to toxic levels.

Yipe.

Yeah, and that severely increases the risk of lactic acidosis, which is a life -threatening condition.

Wow.

You never resume metformin until the provider verifies with lab work that renal function is completely back to normal.

That is a perfect example of connecting the dots.

Okay, so we've used our dashboard.

We find a blockage with the catheter or we spot an electrical glitch on the EKG.

We have to fix the pipes or calm the grid.

Let's look at therapeutic procedures for the pipes.

Yeah.

For narrowed pipes, we use PTCA, percutaneous transluminal coronary angioplasty.

That balloon thing.

Right.

You snake a balloon catheter into the narrowed artery,

inflate it to smash the plaque against the walls and leave a stent to keep it open.

But if the blockage is too severe, you need a CABG, a coronary artery bypass graft.

Where they literally harvest a vein from the leg or an artery from the chest and build a physical detour around the blockage.

Exactly.

And for CABG patients, there is a vital post -operative assessment.

They will have mediastimal chest tubes to drain blood from around the heart.

As the nurse, you monitor that closely.

What are we looking for?

If drainage exceeds 100 to 150 milliliters per hour, you report it immediately.

That isn't normal oozing.

That indicates active internal hemorrhage.

Got it.

Okay, let's pivot to the electrical glitches, the dysrhythmias.

We built the walls and pipes, but when the wiring misfires, the plumbing doesn't matter.

Let's start with sinus bradycardia.

The heart rate is less than 60.

If I see a rate of 45 on the monitor, my first thought is to panic.

But the chapter says we don't always treat this.

Right, because you treat the patient, not the monitor.

Normal for an Olympic marathon runner.

Oh right, because their heart is so strong.

Yeah, their heart is just incredibly efficient.

We only treat bradycardia if the patient is symptomatic, meaning they are dizzy, confused, or hypotensive because their brain isn't getting enough oxygen.

Okay, and if they are symptomatic?

The intervention is administering a medication like atropine to block the parasympathetic breaks, or setting up a transcutaneous pacemaker to externally force a faster rhythm.

Makes sense.

That brings us to atrial fibrillation.

The SA node loses its mind and the atria just quiver, firing 350 to 600 times a minute.

It's chaos.

Yeah.

Now, if the top chambers of the heart are just quivering and not actually giving a strong squeeze, they aren't pumping anything,

my instinct is that the patient just passes out from lack of blood flow.

Is that the immediate danger?

Actually it's something else.

The bottom chambers, the ventricles, still do the heavy lifting of pushing blood to the body.

They will beat irregularly, so cardiac output does drop, but it doesn't stop completely.

Okay, so what's the real threat?

The real insidious danger of AFib is that the blood left sitting in those quivering atria becomes stagnant.

It pools,

and pooling blood forms clots.

And if one of those clots breaks loose?

It shoots straight out into the circulation.

If it goes to the brain, it causes a massive ischemic stroke.

Wow.

That is why administering anticoagulants is an absolute priority for patients in atrial fibrillation.

You have to keep that stagnant blood from clotting.

Okay.

Moving down to the ventricles, PVCs, or premature ventricular contractions.

The text uses terms like bigeminy, which is a PVC every other beat, or trigeminy.

The big warning sign here is the R on T phenomenon.

What exactly is that crashing into?

So in a normal heartbeat, the ventricles contract, and then they have to recharge or repolarize.

That recharge phase is the T wave on an EKG.

If a rogue electrical impulse of PVC fires right as the heart is trying to recharge on the T wave, it sends the electrical grid into absolute chaos.

It can trigger a deadly rhythm, like ventricular tachycardia.

VTAC.

The rate shoots up to 140 to 250 beats per minute.

On the monitor, it looks like wide giant jagged teeth.

Exactly.

And if that chaotic rhythm deteriorates further, you get ventricular fibrillation, or VFib, just coarse disorganized wavy lines.

Right.

And VFib means the battery is dead.

There's no heartbeat, just a quivering sheet of muscle.

There is zero cardiac output, which means there is no pulse.

The immediate clinical action is CPR and defibrillation.

Let's clarify the interventions here, because the text talks about defibrillation, cardioversion, and vagal maneuvers.

What is the mechanical difference?

It's really about how aggressively we need to reset the grid.

Vagal maneuvers, like carotid sinus massage or bearing down for a Valsalva maneuver, are used for fast but stable rhythms.

Oh, like bearing down like you're having a bowel movement.

Exactly.

They physically stimulate the vagus nerve to hit those parasympathetic breaks we talked about earlier.

But if they are unstable, we use electricity.

Right.

Cardioversion is a synchronized shock.

The machine reads the patient's chaotic rhythm and times the shock perfectly to hit right on the R wave,

essentially resetting the grid without causing that R on T chaos we just mentioned.

Okay.

And defibrillation.

That is an asynchronous shock.

It's a massive, immediate blast of electricity used when there is no organized rhythm to synchronize with, like in VFIP.

You typically dial it up to 360 joules for a monophasic defibrillator.

And as the nurse, you must visually check that everyone has cleared the bed three separate times before you hit that button.

Good to know.

So why do these wires suddenly misfire?

Usually it's because the muscle tissue housing them is starving for oxygen, which leads us perfectly to the concept of supply versus demand, coronary artery disease, angina, and myocardial infarction.

Coronary artery disease, or CAD,

is the buildup of atherosclerotic plaque inside the pipes feeding the heart muscle.

As the plaque grows, the pipe narrows.

The text notes, it's highly significant if the left main coronary artery is reduced by just 50%.

Why is that one so important?

Because that single vessel supplies almost all the blood to the massive left ventricle.

Ah, and when that blood flow is reduced, the muscle cries out in pain.

That's angina.

Exactly.

The chapter breaks down three types.

There's stable angina, it's predictable.

You exert yourself, the heart needs more oxygen, it hurts.

You rest or take a nitroglycerin pill to dilate the vessels and it goes away.

Then there's unstable angina, which is a massive red flag.

It's pre -infarction, it's unpredictable, happens at rest, and the pain lasts longer than 15 minutes.

And don't forget variant, or Prince metal's angina.

Oh, right.

Variant isn't caused by a fixed plaque though, right?

Yeah, correct.

It's caused by coronary artery spasms.

The pipe literally clenches shut.

It often happens at the same time every day, usually at rest, and it uniquely shows ST elevation on the EKG during the attack.

But if any of these conditions progress, if that starvation continues and the ischemia isn't reversed,

the tissue actually dies.

Necrosis.

Yeah, that's a myocardial infarction, a full -blown heart attack.

Right.

The pain is described as crushing, it radiates to the jaw or left arm, lasts over 30 minutes, and it is not relieved by rest or nitroglycerin.

Exactly.

The acute stage priorities follow an acronym, M -O -N -A, morphine, oxygen, nitroglycerin, aspirin.

I understand giving oxygen and I understand aspirin to stop platelets from making the clot worse.

But why is morphine such a massive priority?

Is it just to keep them from screaming in pain?

Oh, it's much more mechanical than that.

Severe pain causes immense sympathetic stress.

Your body dumps massive amounts of adrenaline into your bloodstream.

That adrenaline spikes your heart rate and your blood pressure, which forces the starving heart muscle to work even harder against greater resistance.

Oh, wow.

That's the last thing you want.

Exactly.

Morphine kills the pain, which stops the adrenaline dump, which mechanically lowers the heart rate and decreases the heart's demand for oxygen.

It physically saves dying heart tissue.

That makes total sense.

So we treat the MI, we give the thrombolytic drugs within six hours to dissolve the clot, or we get them to the cath lab, we save their life.

Right.

But that tissue that was starved of oxygen didn't just magically bounce back, it died.

It turned into stiff scar tissue.

And that leaves us with a permanent structural problem.

We now have a weak pump.

Precisely.

Surviving an acute MI often evolves into chronic heart failure.

And remember, the heart is a two -sided pump, the left side and the right side.

The textbook offers a classic mnemonic here.

Left is for lungs and right is for the rest of the body.

But let's look at the actual mechanics of why that happens.

If the left ventricle is weak and failing, it can't muster the strength to push blood out the front door into the aorta.

So the incoming blood has nowhere to go.

It backs up out the back door straight into the pulmonary veins and the lungs.

Exactly.

The fluid literally leaks into the lung tissue.

That's why left -sided heart failure presents as pulmonary congestion dyspnea crackles when you listen to the lungs.

And that classic frothy sputum.

And if the right ventricle fails, it can't push blood into the lungs, so the blood backs up its own back door into the systemic venous system.

Right.

You see the pressure build up in the body, jugular vein distension in the neck, fluid weeping into the abdominal cavity causing ascites, an enlarged congested liver and dependent pitting edema in the legs and ankles.

Okay, let's put this into a clinical scenario.

You walk into a room.

Your heart failure patient is suddenly grasping their chest, gasping for air.

Their heart rate is 130 and they are coughing up pink blood -tinged frothy sputum.

That's bad.

The text calls this acute pulmonary edema.

It's a medical emergency.

What is the immediate sequence of actions?

Okay, first, use gravity.

Sit them straight up in a high Fowler's position immediately with their legs dangling.

This forces the fluid down to the bases of the lungs so they have some room to exchange air at the top.

Good.

What's next?

Second, apply high flow oxygen.

Third, ensure you have a patent IV line.

Fourth,

push a rapid acting loop diuretic like furosemide to aggressively force the kidneys to pee out the excess volume.

And you'll insert a Foley catheter to measure exactly how much comes out.

Right, stripped I and O.

Exactly.

Finally, administer morphine sulfate to reduce venous return to the heart and calm their acute suffocating anxiety.

And if the pump failure is so severe that the body isn't getting any blood at all, that cascades into cardiogenic shock.

Profound hypotension, zero tissue perfusion.

The engine has totally flooded and stalled.

Yes.

The heart is just too damaged to sustain life without extreme pharmacological and mechanical hemodynamic support.

Okay, so we've covered the pipes, the wiring, and the pump muscle itself.

What if the muscle is fine, but the protective sac around it or the doors inside it are the problem?

Let's talk about inflammation and structural leaks.

Let's start with the sac.

Pericarditis is inflammation of the pericardium.

The hallmark assessment finding is a pericardial friction.

Rub a harsh, scratchy sound on auscultation as the inflamed layers grind together.

The pain is uniquely worse when the patient lies flat, and it's mechanically relieved by sitting up and leaning forward.

Because it physically pulls the heart away from the inflamed pleura of the lungs, right?

Exactly.

Then there's endocarditis, which is an infection of the inner lining and the valves themselves.

The text notes this is heavily associated with IV drug use.

Very common, yes.

The home care instructions box for endocarditis really stood out to me.

They emphasize a soft toothbrush and instruct the patient absolutely not to floss.

What does flossing have to do with the heart?

Think about the pathway.

Flossing almost always causes tiny micro tears in the gums.

Oh, right.

And the human mouth is packed with bacteria.

Those micro tears create a direct open highway for bacteria to enter the bloodstream.

Once in the blood, those bacteria love to travel straight to the heart and colonize those already vulnerable damaged heart valves, causing a massive secondary infection.

That is a brilliant mechanical connection to remember.

Now, back to that peripartial sac.

Earlier we mentioned it holds 5 to 20 milliliters of fluid.

But if it becomes inflamed or bleeding occurs, and it fills with fluid rapidly, it causes cardiac tamponade.

This is the lethal squeeze I warned about earlier.

The sac can't stretch fast enough, so the fluid physically crushes the ventricles inward.

They simply cannot expand to fill with blood.

What are the signs?

The classic signs are pulses paradoxes, a skyrocketing central venous pressure,

jugular vein distension, but with clear lungs because the fluid isn't backing up into the lung tissue, it's just stuck in the veins.

And distant muffled heart sounds because you're listening through a thick wall of fluid.

The emergency treatment is a pericardiosynthesis, right?

Inserting a long needle through the chest wall to drain the fluid.

The text asks how a nurse evaluates if the procedure worked.

Well, you'll see immediate mechanical relief.

The blood pressure shoots up because the pump can finally fill and push blood again.

The central venous pressure drops because the venous backup is relieved.

And those muffled heart sounds instantly become crisp and clear.

Awesome.

We also need to touch on valvular disease.

Basically valves that become stiff and won't open fully, that's stenosis, or valves that become floppy and won't close fully, allowing backward flow.

That's insufficiency or regurgitation.

Yeah.

And the major NCLEX takeaway here is for patients whose valves are so bad, they get mechanical valve replacements.

Okay.

Because a mechanical valve is a foreign synthetic object sitting in the bloodstream, the body will constantly try to form blood clots on it.

Therefore, these patients require lifelong anticoagulant therapy.

The chapter also brings up cardiomyopathy.

The text notes that treatment is largely palliative, focusing on lifestyle changes.

What's actually happening to the muscle and cardiomyopathy that makes it unfixable?

It's profound structural remodeling.

Depending on the type, the muscle fibers stretch out and become floppy, or they become rigidly thick.

Think of a blown out rubber band.

You can't unstretch it.

Oh yeah.

So palliative care means we use beta blockers and diuretics to artificially reduce the workload on the heart, trying to extend the life of that damaged remodeled pump for as long as humanly possible.

Okay, let's zoom out.

The heart is the engine, but the blood vessels are the highways.

What happens when there's a traffic jam?

Let's look at the peripheral highways, vascular disorders, and hypertension.

The biggest hurdle for nursing students here is differentiating between venous and arterial disorders,

specifically regarding how you position the patient's legs in bed.

Yes, this trips up everyone.

Let's make the mechanics crystal clear.

It all comes down to gravity and flow.

Veins carry deoxygenated blood back up to the heart.

If you have a venous issue, like venous insufficiency or a deep vein thrombosis, the blood is trapped down in the legs.

So you elevate them.

Right.

You elevate the legs above the level of the heart to let gravity help drain that blood back to the center.

But arteries are the exact opposite.

They carry freshly oxygenated blood away from the heart, pushing it down to the toes.

So if a patient has peripheral arterial disease, or PAD, the arteries are narrowed and their legs are literally starving for oxygen.

Exactly.

And that causes intermittent claudication, right?

Severe pain when walking.

And here's the safety alert.

For arterial disease, do not elevate the legs.

Oh, because they already aren't getting blood.

Exactly.

If you elevate arterial legs above the heart, you are forcing an already struggling heart to pump blood uphill against gravity through narrow pipes.

You will completely cut off their circulation.

Wow.

You want to keep arterial legs dependent, meaning dangling down toward the floor, so gravity pulls the blood into the starving feet.

That makes perfect sense.

Next on the highway, aortic aneurysms.

This is a severe dilation, a ballooning out of the artery wall.

There is a hard and fast rule here.

If you assess a patient and visually see a pulsating mass in their abdomen, never palpate it.

Do not touch it.

Pushing on it could pop the aneurysm.

If it does rupture, the patient will report sudden tearing,

severe back or abdominal pain, and they will rapidly bleed to death internally.

Let's test this knowledge with the scenario derived right from the chapter's practice exercises.

Imagine you are on the floor.

Your patient is one day post -up from having an abdominal aortic aneurysm surgically repaired.

Their IV fluids are running at 150 milliliters an hour.

But you check their Foley catheter, and their urine output has dropped from 90 to 50 to just 28 milliliters in the last hour.

Their blood work comes back.

Blood urea nitrogen, or BUN, is 35, and creatinine is 1 .8.

Now, normal BUN is around 10 to 20, and normal creatinine is about 0 .6 to 1 .2.

So these labs are highly elevated.

Do we just document this and continue to monitor, or are we calling the provider?

Oh, you call the provider immediately.

Normal urine output must be at least 30 milliliters per hour.

During that aneurysm surgery, the surgeon likely had to clamps the aorta, which means blood flow to the renal arteries was temporarily cut off.

A sudden drop in urine output below 30, combined with spiking BUN and creatinine, means the kidneys took a severe ischemic hit and are actively failing.

Wow.

This is an acute kidney injury.

You do not wait and see on organ failure.

It always comes back to putting the pieces together.

Finally, the chapter covers hypertension.

We know the new guidelines define normal blood pressure as a systolic below 120 and a diastolic below 80.

But the real danger zone the NCLE -X tests is a hypertensive crisis.

That's a systolic over 180 or a diastolic over 120.

The immediate priority is administering ICV antihypertensives to slowly bring that pressure down while constantly assessing their neurological status.

Because of the risk to the brain.

Exactly.

That extreme pounding pressure can cause rapid target organ damage.

It blows out the fragile vessels in the brain causing strokes, destroys the retinas, and spreads the kidneys.

Wow.

Well, we have mapped the entire system today.

We've covered the structural anatomy, the diagnostic dashboard, the chaotic wiring, the starved pipes, the failing pump muscle, the inflamed protective sac, and the peripheral highways.

We really did.

And if I can leave you with one final thought as you prepare for this exam.

The NCLE -X isn't just trying to see if you can memorize a lab value or recognize a widened QRS complex on an EKG strip.

Right.

It's testing if you understand the mechanics of life and death.

Behind every dropping urine output, behind every alarm on that monitor is a human being whose life depends entirely on your ability to connect these dots.

Don't just treat the monitor.

Treat the patient.

Don't just treat the monitor.

Treat the patient.

I love that.

Think about that hidden wiring and plumbing and use the clues to see the whole picture.

On behalf of the last minute lecture team, you've got this.

Thank you for starting with us.

Good luck on your NCLE -X and we'll see you on the floor.