Nursing Field Notes / Cardio · Pathophysiology Course

🫀 CHEST-PAIN SET NG-017 Stable vs Unstable NG-098 Variant (Prinzmetal) NG-071 Myocardial Infarction NG-145 Atherosclerosis

Angina 💢

Stable vs. Unstable — the same pipe, two different stories

NG-017 CARDIO ADHD-friendly visual edition

Angina is the heart muscle shouting that it isn't getting enough oxygen. Stable angina is chest pain induced by physical activity — stairs, yard work, sex, anything that causes exertion — and it stops when the activity stops. Unstable angina is pain at REST — a warning sign for an MI, because the coronary arteries are more severely narrowed.

📄 Simple Nursing original — opens in Drive →

⚖️ Supply < DemandAngina = the heart demands more O₂ than the narrowed coronary can supply.

🟢 S = Stable · Safer · Stops with restExertion brings it on; rest takes it away. Predictable.

🔴 U = Unstable · Unsafe · Unrelieved at restPain at rest. Warning sign for MI. Treat as an emergency.

💊 NitrO = O₂ to the heartNO “-afil” drugs (sildenafil & friends) — the combination can be fatal.

🧨

WHY IT HURTS

STEP 1 · SUPPLY vs DEMAND

The heart muscle feeds itself through the coronary arteries. Narrow those pipes and the muscle starts complaining.

🫀 The coronary artery tree — the heart's own blood supply

EXAM TIP The coronaries branch off the aorta just above the aortic valve and wrap around the outside of the heart. They fill during DIASTOLE — when the heart relaxes. That is why a very fast heart rate makes angina worse: less relaxing time = less coronary filling.

🧠 “LAD = the widow-maker's highway.” LAD → Left front. Circumflex → Curves around the side. RCA → Right + the Rhythm nodes.

⚖️ The one equation behind every kind of angina

Answer first: angina happens the moment oxygen DEMAND outruns oxygen SUPPLY. Everything you do for a client with angina either lowers demand or raises supply.

🧠 “The muscle is yelling: HEY, I don't have enough oxygen!” That shout is the pain. Ischemia is reversible — infarction is not.

🧱 Cross-section of the artery — how a plaque narrows the pipe

Angina starts with atherosclerosis. Look at the wall layers: endothelium → intima → media (smooth muscle) → adventitia. Plaque builds inside the intima and pushes into the lumen.

🧠 “Stable plaque = a speed bump. Ruptured plaque = a road-block being built while you drive.” That is exactly why unstable angina is unpredictable.

🟢

STABLE ANGINA

SIDE A · PREDICTABLE

Classic exertional angina — it shows up when you work, and it leaves when you stop.

🚶 Patho & causes — chest pain induced by physical activity

Stable angina is chest pain induced by any physical activity — walking up stairs, working in the yard, or even sex. Anything that causes exertion! There is less oxygen delivered to the heart muscles during the physical exertion, so the muscle produces pain — the heart saying “HEY, I don't have enough oxygen!” Naturally, the pain stops when the physical activity stops.

🪜Stairs

🌿Yard work

🛏️Sex

🥶Cold air

🍔Heavy meal

😤Stress

🧠 S · S · S — Stable Angina · Safer Angina · Stops with rest. Three S's, one idea.

📈 The exertion curve — stable pain has a shape you can draw

🧠 If you can predict what brings the pain on and predict what makes it stop, it's stable. Lose the prediction, lose the stability.

🔴

UNSTABLE ANGINA

SIDE B · EMERGENCY

Pain at rest. This is acute coronary syndrome until proven otherwise.

🚨 Pain at rest! — a warning sign for MI

Pain at rest! This is a warning sign for an MI (heart attack). It is the more severe angina because it means more severe narrowing of the coronary arteries, resulting in less oxygen to the heart muscles.

At rest, or with minimal effort
New onset angina in someone who never had it
More frequent, more intense, or lasting longer than the client's usual pattern
Not relieved by rest or by the usual nitroglycerin

🧠 U · U · U — Unstable Angina · Unsafe Angina · Unrelieved pain at rest.

🔬 Partial vs. total occlusion — where angina ends and MI begins

Same artery, two amounts of clot. Partial occlusion starves the muscle (ischemia — reversible). Total occlusion kills it (infarction — permanent).

HIGH YIELD Unstable angina and NSTEMI look identical at the bedside. The difference is the troponin: unstable angina = troponin stays normal; NSTEMI = troponin rises. Both are treated as acute coronary syndrome.

🧠 “Trop tells the truth.” Pain can lie, the ECG can be subtle — the troponin tells you whether muscle actually died.

🚨 Do this NOW for unstable / rest pain

Stop activity, sit or lie down, stay with the client.

Call for help / activate EMS — this is a suspected ACS.

12-lead ECG and cardiac troponins.

Oxygen if hypoxemic, IV access, continuous cardiac monitoring, vital signs.

Aspirin (chewed) and nitroglycerin as prescribed — after checking blood pressure and PDE-5 inhibitor use.

🧠 “Rest pain gets a rhythm strip.” Any chest pain at rest earns an ECG — do not talk yourself out of it.

♀️ Atypical presentations — the ones that get missed

Not everyone clutches their chest. Women, older adults, and people with diabetes more often present with:

Fatigue that is new and unexplained
Shortness of breath without chest pain
Nausea / indigestion-type discomfort
Jaw, neck, back or epigastric discomfort
Dizziness or a sense of doom

❌ Never rule out cardiac pain just because it is not “crushing substernal chest pain.”

🧠 Diabetic neuropathy can silence the pain — a “silent MI” still infarcts. Trust the vitals and the ECG, not just the complaint.

🔎

TELL THEM APART

SIDE A vs SIDE B

One table. If you own this table you own the question.

⭐ Stable vs Unstable vs Variant vs MI

Feature	🟢 STABLE	🔴 UNSTABLE	🌙 VARIANT	💀 MI
Trigger	Physical exertion, cold, stress, heavy meal	At rest or minimal effort	Often at rest, night / early morning	Any time, often at rest
Mechanism	Fixed atherosclerotic narrowing	Plaque rupture + partial thrombus	Coronary artery vasospasm	Total occlusion → necrosis
Relieved by	Rest and/or nitroglycerin	Not reliably relieved	Nitroglycerin / calcium channel blockers	Not relieved — needs reperfusion
Duration	Brief — minutes	Longer, more frequent, more intense	Short but recurrent	Prolonged
Troponin	normal	normal	usually normal	ELEVATED
Bottom line	Predictable · manage & teach	ACS — emergency	Spasm — see NG-098	Muscle death — see NG-071

🧠 “Stable Stops. Unstable Undoes you. Variant is Vasospasm. MI = Muscle Is dead.”

🧪 Diagnostics you'll see ordered

12-lead ECG — first, and fast
Cardiac troponin — serial draws; the marker that separates angina from MI
Stress test (exercise or pharmacologic) — for stable angina, never during unstable pain
Coronary angiography / cardiac cath — sees the actual narrowing, can stent it
Lipid panel, A1c, BP — the risk factors driving the plaque

🧠 Stress test = stress the STABLE. Stressing an unstable client on purpose is the wrong answer every single time.

🎯 Modifiable risk factors — the real long game

Smoking — cessation is the single highest-yield change
Hypertension and hyperlipidemia control
Diabetes / glucose control
Obesity, sedentary lifestyle, poor diet
Stress management & sleep

Non-modifiable: age, male sex, family history, ethnicity. See NG-145 Atherosclerosis.

🧠 The plaque took decades to build — the teaching is about slowing it down, not erasing it.

💊

NITROGLYCERIN

TREATMENT · TEACH THIS COLD

The drug the exam loves. Read every line — most of these are pure test points.

💥 How it works — NitrO = O₂ to the heart

Nitroglycerin is a vasodilator. It relaxes the smooth muscle in blood vessels, which dilates the veins (less blood returning to the heart = less preload = less work) and dilates the coronary arteries (more oxygen delivered). Net effect: oxygen demand drops and oxygen supply rises — the pain stops.

🧠 “Nitr-O gives O₂.” The O in the middle of the drug name is the oxygen it sends to the heart.

🚨 The absolute contraindication — PDE-5 inhibitors

❌ NO “-afil” drugs with nitroglycerin. Sildenafil, tadalafil, vardenafil + nitrates = profound, potentially FATAL hypotension.

Both drug classes are vasodilators. Stacked together the blood pressure can bottom out and the client can arrest. Always ask about erectile-dysfunction and pulmonary-hypertension medications before giving nitroglycerin — including the ones bought without a prescription.

Practice varies on the exact interval, but the standard teaching is that nitrates must be withheld for at least 24 hours after sildenafil or vardenafil, and at least 48 hours after tadalafil.

🧠 “-afil = afill coffin.” Harsh, but you will never forget it. If the answer choice pairs nitro with an “-afil,” that's the wrong answer.

💊 Sublingual nitroglycerin — how the client takes it

Answer first: 0.4 mg SL tablet (or metered spray), 1 dose, then repeat every 5 minutes up to 3 doses total. Call 911 if the pain is unimproved or worsening 5 minutes after the FIRST dose — do not wait for all three.

🧠 “Sit, slip it under, wait five, call.” Sit down first — nitro drops blood pressure and standing up mid-dose is how people fall.

📦 Storage — the sneaky exam points

✅ YESOriginal dark container · a purse is OK · cool, dark, dry

❌ NO LIGHTLight degrades it — keep it in the amber bottle

❌ NO HEATNot the car, not a hot pocket

❌ NOT a pill boxNot a plastic bag, not loose in a pocket

🗓️ Replace the supply every 6 months (or per the manufacturer's expiration) — old tablets lose potency.

🧠 “Dark bottle, cool purse, new every 6 months.” A tablet that doesn't tingle or doesn't work may simply be dead.

🩹 Transdermal patch — the other half of the question

1 patch daily — scheduled, NOT PRN
One patch at a time — never two
Rotate the site daily · clean, dry, hairless area on the upper body (chest, upper arm, subclavian area)
❌ Not on hairy, scarred, burned, callused or broken skin
Showering is fine · wash hands after applying
Nurses wear gloves — absorbing it causes a major headache
A nitrate-free interval (commonly 10–12 hours, usually overnight) is prescribed to prevent tolerance

TEST TIP Patch fell off more than an hour ago and chest pain starts? Take the SL nitro (tablet or spray) — a new patch can take 40–60 minutes to work.

🧠 “Patch is prevention, tablet is rescue.” The patch never treats an active attack.

🎯 The goal, in the client's own words

NO chest pain during daily activities — “I can comb my hair, get dressed, put on make-up, and make my bed without chest pain.” That is what a successful plan looks like, and it is how the exam words the evaluation question.

💇Comb hair

👕Get dressed

💄Make-up

🛏️Make the bed

🚿Shower

🍳Cook a meal

Other prescribed therapies you'll see alongside nitrates: aspirin/antiplatelets, beta blockers (NG-176), calcium channel blockers (NG-195), statins (NG-242), and revascularization with PCI/stent or CABG.

🧠 “Activities of daily living without pain” is the outcome statement. If the client can do their ADLs pain-free, the plan is working.

⚡

QUICK RECALL

SAY IT OUT LOUD

🟢 Stable · Safer · Stops with restExertional, predictable, brief.

🔴 Unstable · Unsafe · UnrelievedPain at rest = warning sign for MI.

💊 0.4 mg SL · q5min · max 3Call 911 if pain persists 5 min after dose 1.

☠️ Nitro + “-afil”Sildenafil & friends = fatal hypotension. Always ask.

🎯 Cover & check — 7 rapid-fire questions

Q1: What triggers stable angina, and what relieves it?

Physical exertion — stairs, yard work, sex, anything that causes exertion. It stops when the physical activity stops (and responds to nitroglycerin).

Q2: What is the single defining feature of unstable angina?

Pain at REST. It means more severe narrowing of the coronary arteries and it is a warning sign for an MI.

Q3: A client takes one SL nitroglycerin tablet and 5 minutes later the pain is the same. What do you teach them to do?

Call 911 — after the first dose, if pain is unimproved or worse at 5 minutes. They may take up to 3 doses total, 5 minutes apart, while help is on the way.

Q4: Which medication class is an absolute contraindication with nitrates, and why?

PDE-5 inhibitors — the “-afil” drugs (sildenafil, tadalafil, vardenafil). Both are vasodilators; together they can cause profound, potentially fatal hypotension.

Q5: The client says “this nitroglycerin gives me a headache — should I stop it?”

Headache is an expected/normal side effect of nitroglycerin, not a reason to stop. Hypotension is the adverse effect to watch — teach slow position changes and sitting down before taking a dose.

Q6: How do you tell unstable angina from an NSTEMI?

The troponin. Unstable angina — troponin stays normal (ischemia only). NSTEMI — troponin rises (muscle actually died). Both are managed as acute coronary syndrome.

Q7: Where does the nitroglycerin patch go, how often, and what's the one thing the nurse must do?

One patch daily (scheduled, not PRN), on a clean, dry, hairless area of the upper body, rotating sites daily — never on broken, scarred, burned or callused skin. The nurse wears gloves, because skin contact causes a major headache. A nitrate-free interval is used to prevent tolerance.