NCLEX Cardiac Review: ACS, Heart Failure, and Arrhythmias

Quick answer: For NCLEX cardiac questions, establish stability first: unstable patients get immediate treatment such as cardioversion or defibrillation. The STEMI target is primary PCI within 90 minutes of first medical contact, with oxygen only for SpO2 under 90% or respiratory distress. Sort heart failure by side (left backs up into the lungs, right into the systemic circulation), try vagal maneuvers before adenosine for stable SVT, and hold digoxin for an adult apical pulse under 60.

Cardiac questions on the NCLEX will test your clinical judgment under pressure — chest pain scenarios, telemetry strips, heart failure teaching, and rapid rhythm recognition. If you can triage the cardiac patient correctly, interpret the rhythm, and anticipate the medication, you will move through this content domain quickly on test day.

Key takeaways

• Stability first. Always establish hemodynamic stability (ABC and mental status) before choosing an intervention — unstable patients get immediate treatment like cardioversion or defibrillation.
• STEMI is time-critical. The target is primary PCI within 90 minutes of first medical contact; oxygen is no longer routine and is given only if SpO2 is under 90% or there is respiratory distress.
• Sort heart failure by side. Left-sided failure backs up into the lungs (pulmonary congestion); right-sided failure backs up into the systemic circulation (systemic edema).
• Teach what prevents readmission. MAWDS — daily weights, low sodium, medication adherence, and symptom self-monitoring — drives most heart failure discharge answers.
• Match the rhythm to the action. Stable SVT gets vagal maneuvers first, then adenosine; pulseless VT or VF gets CPR and defibrillation.
• Know the high-yield drug holds. Hold digoxin if apical HR is under 60 in adults; hypokalemia potentiates digoxin toxicity; hold beta-blockers for HR under 60 or SBP under 90 and never stop them abruptly.

How the NCLEX frames cardiac questions

Expect scenarios that mix assessment findings, telemetry, labs, and medications. The test is less interested in whether you can memorize ejection fractions and more interested in whether you can recognize deterioration, prioritize the next nursing action, and identify the teaching point a patient will actually need at discharge. Cardiac content can appear in any item format: standard multiple choice, select all that apply, and NGN items such as drag-and-drop, bowtie, and matrix.

Before you memorize anything else, lock down these three priorities you will lean on all day:

• ABC and tissue perfusion drive prioritization. A patient with chest pain and hypotension outranks a stable post-op patient with mild pain.
• Time is myocardium. In STEMI, every minute of delay costs cardiac muscle. Reperfusion targets are specific and testable.
• Teach what prevents readmission. Daily weights, sodium restriction, and symptom self-monitoring matter more than physiology recitation.

Acute coronary syndrome (ACS): STEMI vs NSTEMI

ACS is a spectrum — unstable angina, NSTEMI, and STEMI — differentiated by ECG changes and cardiac biomarkers. You will not memorize every nuance, but you must know the triage.

Recognition

• STEMI: ST-segment elevation in two contiguous leads. Troponin will rise. This is an emergency; the coronary artery is occluded.
• NSTEMI: No ST elevation, but troponin is positive. ST depression or T-wave inversion may be present.
• Unstable angina: Chest pain at rest or worsening pattern, but troponin is negative.

Reperfusion priorities

The ACC/AHA target for STEMI is primary PCI within 90 minutes of first medical contact (FMC-to-device time; older sources say door-to-balloon, which starts at hospital arrival). If PCI is unavailable within 120 minutes of first medical contact, fibrinolytic therapy is considered, provided there are no contraindications (active bleeding, recent stroke, severe uncontrolled hypertension).

The “MONA” acronym is outdated

You may still see MONA (morphine, oxygen, nitroglycerin, aspirin) in older review books, but current practice has moved on:

• Oxygen is no longer routine — only administer if SpO2 is less than 90% or the patient is in respiratory distress. Hyperoxia can worsen outcomes.
• Aspirin 162–325 mg chewed, given immediately if no contraindication.
• A P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) is added with aspirin — dual antiplatelet therapy.
• An anticoagulant (heparin or enoxaparin) is started based on protocol.
• Nitroglycerin sublingual for ongoing ischemic pain — hold if SBP is under 90 or the patient has taken a phosphodiesterase inhibitor (sildenafil, tadalafil) within 24–48 hours.
• Morphine is reserved for refractory pain; it is not a first-line intervention.

Clinical pearl: If the stem describes a patient who just took sildenafil and now has chest pain, do not give nitroglycerin. The combination drops blood pressure dangerously.

Heart failure: LHF vs RHF and the MAWDS teaching bundle

The NCLEX loves to ask you to sort symptoms by side and to identify the discharge teaching point that prevents readmission.

Left-sided heart failure

Blood backs up into the lungs. Expect pulmonary congestion: crackles, dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, pink frothy sputum, and S3 gallop. If pulmonary edema develops, the patient needs high-Fowler’s position, oxygen, IV loop diuretic (furosemide), and close monitoring.

Right-sided heart failure

Blood backs up into the systemic circulation. Expect systemic edema: jugular venous distention, hepatomegaly, ascites, peripheral edema, and weight gain. Right-sided failure most often follows left-sided failure, but cor pulmonale (right-sided failure from chronic lung disease) is also tested.

MAWDS discharge teaching

Use MAWDS to anchor your answer when the stem asks what the patient needs at discharge:

• Medications: Take as prescribed, never skip diuretics or beta-blockers.
• Activity: Balance rest with gradual activity; cardiac rehab is evidence-based.
• Weight: Daily weights at the same time, same scale, same clothing. Call the provider for a gain of 2–3 pounds in 24 hours or 5 pounds in a week.
• Diet: Low sodium (typically under 2,000 mg/day), fluid restriction if ordered.
• Symptoms: Report increasing dyspnea, edema, orthopnea, or new cough.

Dysrhythmias you must recognize

Supraventricular tachycardia (SVT)

Narrow-complex, regular, rapid (150–250 bpm), usually without visible P waves. If the patient is stable: vagal maneuvers first (Valsalva, carotid massage by the provider, cold water to the face). If vagal maneuvers fail, adenosine 6 mg rapid IV push followed by a 20 mL saline flush; may repeat at 12 mg. Warn the patient they will feel a brief pause — it is unsettling but expected. If the patient is unstable (hypotension, altered mental status, chest pain), synchronized cardioversion.

Ventricular tachycardia

• VT with a pulse, stable: Antiarrhythmic (amiodarone) and close monitoring.
• VT with a pulse, unstable: Synchronized cardioversion.
• Pulseless VT or VF: CPR and defibrillation — unsynchronized shock. This is the rhythm that kills quickly; do not pause to think.

Atrial fibrillation

Irregularly irregular rhythm, no discrete P waves. Two decisions drive care:

• Rate vs rhythm control: Most patients get rate control with beta-blockers, diltiazem, or digoxin. Rhythm control (cardioversion, amiodarone) is used selectively.
• Anticoagulation: Stroke risk is the silent killer. CHA2DS2-VASc scoring drives the decision. DOACs (apixaban, rivaroxaban, dabigatran) are preferred over warfarin for most non-valvular AFib. Warfarin still rules for mechanical valves and some valvular AFib — teach INR monitoring, consistent vitamin K intake, and bleeding precautions.

Bradycardia and heart blocks

Symptomatic bradycardia: atropine 1 mg IV, may repeat every 3–5 minutes to a total of 3 mg. If atropine fails, transcutaneous pacing, then dopamine or epinephrine infusion. Complete (third-degree) heart block is a pacemaker indication — do not expect atropine to fix it.

Hypertensive urgency vs emergency

• Urgency (now called “severe hypertension” in the 2025 AHA/ACC guideline): BP over 180/120 without acute end-organ damage. Treated by starting, restarting, or intensifying oral medications with close follow-up, not rapid IV lowering; the patient is not in crisis.
• Emergency: BP over 180/120 with acute end-organ damage — chest pain, stroke symptoms, papilledema, AKI, pulmonary edema. IV antihypertensives (nicardipine, labetalol, hydralazine) in an ICU setting. Lower the MAP by no more than 25% in the first hour to avoid stroke from cerebral hypoperfusion.

Cardiac medications the NCLEX loves

Digoxin

Therapeutic level 0.5–2.0 ng/mL. Toxicity: nausea, vomiting, anorexia, visual disturbances (halos, yellow-green vision), bradycardia, and new dysrhythmias. Hypokalemia potentiates digoxin toxicity — a patient on a loop diuretic and digoxin needs aggressive K+ monitoring. Hold digoxin if apical HR is under 60 in adults (under 90 in infants, under 70 in children). Antidote for severe toxicity: digoxin immune Fab (Digibind).

Beta-blockers

Hold if HR is under 60 or SBP is under 90 — confirm with the provider. Do not stop abruptly; rebound tachycardia, hypertension, and angina can follow. Teach patients to rise slowly (orthostatic hypotension) and that these drugs can mask hypoglycemia in diabetes (the tachycardic warning sign is blunted).

ACE inhibitors and ARBs

Monitor potassium (hyperkalemia risk) and creatinine. ACE inhibitors cause a dry, persistent cough in some patients — switch to an ARB. Both are contraindicated in pregnancy.

Statins

Monitor LFTs and teach patients to report new muscle pain (rhabdomyolysis risk). Grapefruit juice inhibits metabolism of simvastatin and lovastatin — teach avoidance.

Pacemakers and ICDs — what to teach

• No MRI unless the device is MRI-conditional and cleared by cardiology.
• Avoid strong magnetic fields; hold cell phones on the opposite side.
• Check pulse daily; report a rate below the programmed lower limit.
• ICD firing: sit or lie down; if it fires once and the patient feels well, notify the provider. Multiple firings or symptoms after firing — call 911.
• Carry device identification.

Putting it together on test day

When a cardiac question appears, run this mental sequence:

1. Is the patient stable? Assess airway, breathing, circulation, and mental status. Unstable patients get immediate interventions (cardioversion, defibrillation, rapid-response fluids, emergency meds).
2. What rhythm or syndrome is this? Narrow vs wide, regular vs irregular, fast vs slow. Chest pain with ST elevation = STEMI until proven otherwise.
3. What is the next nursing action? Position, oxygen if indicated, IV access, 12-lead ECG, notify provider, prepare meds.
4. What does the patient need to know? Discharge teaching questions nearly always reward the answer that prevents readmission or catches early deterioration.

Pair this review with cardiac pharmacology and your lab values reference so you can move through troponin, BNP, INR, and electrolyte questions without hesitation. For a full overview of next-gen item formats, see the NGN question types guide.

Cardiogenic shock is compared side by side with the other shock states in our types of shock guide.

Frequently Asked Questions

What is the quick difference between left-sided and right-sided heart failure?

Left-sided heart failure backs blood up into the lungs, so you see pulmonary congestion — crackles, dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, pink frothy sputum, and an S3 gallop. Right-sided failure backs blood up into the systemic circulation, so you see systemic edema — jugular venous distention, hepatomegaly, ascites, peripheral edema, and weight gain. Right-sided failure most often follows left-sided failure.

What separates a STEMI from an NSTEMI on the NCLEX?

A STEMI shows ST-segment elevation in two contiguous leads with a rising troponin, meaning the coronary artery is occluded — this is an emergency, and the target is primary PCI within 90 minutes of first medical contact. An NSTEMI has a positive troponin but no ST elevation; you may instead see ST depression or T-wave inversion. Unstable angina presents with chest pain at rest or a worsening pattern but a negative troponin.

When should the NCLEX answer use vagal maneuvers versus adenosine for SVT?

For stable SVT — narrow-complex, regular, rapid, with the patient alert and hemodynamically stable — vagal maneuvers come first, such as bearing down (Valsalva), carotid massage by the provider, or cold water to the face. Only if vagal maneuvers fail do you give adenosine 6 mg rapid IV push followed by a 20 mL saline flush, which may be repeated at 12 mg. If the patient is unstable (hypotension, altered mental status, chest pain), the answer shifts to synchronized cardioversion.

Why does hypokalemia matter so much for a patient on digoxin?

Hypokalemia potentiates digoxin toxicity, so a low potassium level makes toxic effects more likely even at a normal digoxin dose. This matters most when a patient takes both a loop diuretic and digoxin, because the diuretic can drive potassium down — these patients need aggressive potassium monitoring. Watch for toxicity signs such as nausea, vomiting, anorexia, visual disturbances like halos or yellow-green vision, bradycardia, and new dysrhythmias.

What is the most important heart failure discharge teaching point?

Daily weights are the cornerstone. Teach the patient to weigh at the same time, on the same scale, in the same clothing, and to call the provider for a gain of 2–3 pounds in 24 hours or 5 pounds in a week, because that signals fluid retention before decompensation. The MAWDS bundle rounds this out: take medications as prescribed, balance activity with rest, follow a low-sodium diet, and report worsening symptoms like dyspnea, edema, orthopnea, or a new cough.