Nursing care
Myocardial Infarction nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Myocardial infarction nursing care starts with recognising chest pain, dyspnoea or diaphoresis, obtaining a 12-lead ECG within 10 minutes, and giving oxygen, aspirin, nitroglycerin and morphine as ordered. Troponin rises in 3–4 hours and stays elevated for up to two weeks, while CK-MB normalises in 2–3 days, making it the marker of choice for detecting reinfarction.
What it is and why it happens
A myocardial infarction occurs when a coronary artery is occluded, usually by a ruptured atherosclerotic plaque with superimposed thrombus, and the myocardium supplied by that vessel becomes ischaemic and then necrotic if flow is not restored. The degree of damage depends on which artery is occluded, how completely, and how quickly perfusion is restored; this is why door-to-balloon time is tracked as a quality metric rather than treated as a soft target.
ST-elevation MI (STEMI) reflects full-thickness, transmural infarction from complete occlusion and needs emergency reperfusion. Non-ST-elevation MI (NSTEMI) reflects partial occlusion or a subendocardial infarct, confirmed by rising cardiac biomarkers without the classic ST elevation, and is managed medically first with angiography timed by risk. Both share the same underlying process of plaque rupture and thrombosis, so risk factor modification, which is atherosclerosis prevention, applies to both.
How it presents — what you will actually see
Classic presentation is substernal chest pain or pressure, often described as crushing or squeezing, radiating to the left arm, jaw or back, lasting more than 15–20 minutes and unrelieved by rest. Associated findings include diaphoresis, nausea, dyspnoea, and a sense of impending doom. Vital signs may show tachycardia, hypertension from sympathetic activation, or hypotension if the infarct is large enough to impair cardiac output.
Presentation is frequently atypical, and this is where missed diagnoses happen. Women, older adults and patients with diabetes more often present with fatigue, dyspnoea, epigastric discomfort, or nausea without classic chest pain, because autonomic neuropathy or a different symptom threshold blunts the typical pain pattern. Treat any of these presentations in a patient with cardiac risk factors as a possible MI until the ECG and biomarkers say otherwise, rather than waiting for textbook pain.
Nursing assessment priorities
Obtain a 12-lead ECG within 10 minutes of any suspected cardiac chest pain, since this single test decides the treatment pathway between STEMI reperfusion and NSTEMI risk stratification. Assess pain using a consistent scale and reassess after each intervention, because a falling pain score is one of your best bedside indicators that perfusion is improving. Auscultate heart and lung sounds for a new murmur, an S3 gallop, or crackles, which can signal papillary muscle involvement or developing heart failure.
Draw serial cardiac biomarkers on the timeline your protocol specifies, and interpret them correctly. Troponin rises in 3–4 hours and stays elevated for up to two weeks, which makes it highly sensitive but poor for detecting a second event on top of a recent one. CK-MB returns to normal in 2–3 days, so a fresh CK-MB rise in a patient still troponin-positive from a prior infarct is what confirms reinfarction. Continuous cardiac monitoring is essential in the first 24–48 hours, when dysrhythmias are most likely.
Interventions and what to do first
The first-line bundle, often remembered as MONA, is given in the order the patient's condition demands rather than by rote: oxygen if saturation is below 90%, nitroglycerin for pain unless the patient is hypotensive or has taken a phosphodiesterase inhibitor recently, aspirin 162–325 mg chewed for its rapid antiplatelet effect, and morphine for pain unrelieved by nitrates. Aspirin is given even if the patient reports a prior dose that day, since the antiplatelet effect is what matters, not novelty.
For STEMI, time is muscle: prepare the patient for emergency percutaneous coronary intervention or, where PCI is unavailable within the window, administer fibrinolytics per protocol after screening for contraindications such as recent surgery, active bleeding or haemorrhagic stroke history. For NSTEMI, anticoagulation and antiplatelet therapy are started while angiography is arranged on a risk-stratified timeline. Maintain IV access, keep the patient on bed rest with the head of bed elevated for comfort, and have resuscitation equipment immediately available given the arrhythmia risk in the first hours.
Complications to watch for
Dysrhythmias are the most common early complication and the leading cause of death before hospital arrival; ventricular fibrillation is the classic lethal rhythm in the first hour, which is why continuous monitoring is non-negotiable. Heart failure follows if enough myocardium is lost to impair pump function, presenting as crackles, jugular venous distension, or a new S3.
Cardiogenic shock develops when a large infarct drops cardiac output enough to cause hypotension, cool clammy skin and oliguria, and it carries a high mortality even with treatment. Mechanical complications, though less common, are severe when they occur: papillary muscle rupture causes acute mitral regurgitation, and free wall or septal rupture causes sudden haemodynamic collapse, both typically in the first week. Pericarditis, either early post-infarction or as delayed Dressler syndrome weeks later, presents with positional chest pain and a friction rub and should not be mistaken for reinfarction.
Patient teaching before discharge
Teach the patient to recognise recurrent symptoms, when to take sublingual nitroglycerin, and when to call emergency services rather than driving themselves in, specifically if pain persists after one dose or worsens. Review every discharge medication by purpose: aspirin and a second antiplatelet agent to prevent clot formation, a beta-blocker to reduce myocardial oxygen demand, a statin regardless of baseline cholesterol, and an ACE inhibitor if ejection fraction is reduced.
Address modifiable risk factors directly: smoking cessation has the single largest impact on reducing recurrence, alongside dietary sodium and saturated fat reduction, blood pressure and glucose control, and a supervised return to activity through cardiac rehabilitation. Set expectations for the return-to-activity timeline, including when driving, sexual activity and work can resume, since patients frequently under- or overestimate this and either deteriorate through overexertion or become deconditioned through excessive caution.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our cardiovascular practice questions are the closest set to what this page covers.
Common questions
Why draw both troponin and CK-MB if troponin is more sensitive?
Troponin stays elevated for up to two weeks, so it cannot distinguish a new event from a recent one. CK-MB normalises within 2–3 days, so a new CK-MB rise in a patient who is still troponin-positive is the marker that confirms reinfarction.
Why is aspirin given even if the patient took some earlier that day?
The dose given in the acute setting is for its immediate antiplatelet effect on the current clot, not as a first dose of the day. A full chewed dose of 162–325 mg is given regardless of an earlier lower dose, unless there is a true contraindication such as active bleeding or a documented allergy.
What distinguishes STEMI from NSTEMI in the nursing plan?
STEMI shows ST elevation on ECG from complete coronary occlusion and needs emergency reperfusion, either PCI or fibrinolytics, on an urgent timeline. NSTEMI shows biomarker rise without ST elevation from partial occlusion and is managed with anticoagulation and antiplatelet therapy while angiography is scheduled by risk stratification rather than as an immediate emergency.
What is the priority nursing action for suspected MI chest pain?
Obtain a 12-lead ECG within 10 minutes, since it determines the treatment pathway before any medication decision is finalised. Oxygen, aspirin, nitroglycerin and IV access follow immediately alongside it, not after.
More on cardiovascular
Guides on this