Post-Myocardial Infarction

Definition

A myocardial infarction (MI) — a heart attack — occurs when a coronary artery is blocked and part of the heart muscle is starved of oxygen and begins to die. Heart attacks are classified as ST-elevation MI (STEMI), where an artery is completely occluded and emergency reperfusion is required within minutes to hours, or non-ST-elevation MI (NSTEMI), where the blockage is partial. This page focuses on recovery after an MI; for the underlying disease see coronary artery disease.

Pathophysiology

Plaque rupture and thrombosis

Most infarcts are caused by rupture or erosion of an atherosclerotic plaque in a coronary artery wall. The exposed lipid core triggers platelet aggregation and thrombus formation, occluding the vessel. Notably, the culprit plaque is frequently not the most stenotic one — which is why a normal stress test months earlier does not exclude the risk, and why plaque stabilisation with statins matters as much as revascularisation.

Myocardial injury and time

Myocardium supplied by the occluded vessel becomes ischaemic within minutes and begins to die within 20 to 30 minutes, with the infarct extending from the inner endocardium outwards over the following hours. This is the basis of “time is muscle”: the volume of myocardium salvaged falls steeply with every hour of delay to reperfusion.

Healing and remodelling

Necrotic muscle is cleared by inflammatory cells over days and replaced by collagen scar over weeks. Scar does not contract, so if the infarct is large the ventricle dilates and changes shape — adverse remodelling — progressively reducing ejection fraction and leading to heart failure. Much of secondary prevention pharmacology, particularly ACE inhibitors and beta-blockers, works by limiting this process.

Electrical consequences

The border zone between scar and healthy muscle conducts abnormally and provides the substrate for re-entrant ventricular arrhythmia, which is the main mechanism of sudden death both acutely and in the months afterwards.

Co-morbidities

MI shares its risk factors and its company with the rest of cardiovascular disease: hypertension, diabetes, dyslipidaemia, chronic kidney disease, obesity, obstructive sleep apnoea, peripheral arterial disease and smoking. Anxiety and depression follow in a substantial proportion and materially affect recovery, adherence and outcome — they are co-morbidities of the event itself, not merely of the person. Coexisting COPD complicates both symptom interpretation and beta-blocker prescribing, though cardioselective agents are generally safe and under-used in this group.

Prevalence

Coronary heart disease, of which MI is the acute manifestation, remains a leading cause of death in Australia, with tens of thousands of heart attacks each year. Mortality has fallen substantially over three decades through faster reperfusion, better secondary prevention and reduced smoking — but the number of people living after an MI has risen correspondingly, which shifts the clinical challenge from survival to long-term function and prevention. Rates are higher, and outcomes worse, in rural and regional Australia and among Aboriginal and Torres Strait Islander people.

Causes and risk factors

• Smoking — the single most powerful modifiable risk factor, and the one where cessation delivers the fastest benefit.
• Hypertension, dyslipidaemia and diabetes.
• Physical inactivity, poor diet, obesity and excess alcohol.
• Chronic kidney disease and inflammatory conditions such as rheumatoid arthritis.
• Psychosocial factors — chronic stress, social isolation and depression are independent contributors, not soft ones.
• Non-modifiable — age, male sex, family history of premature coronary disease, and ethnicity.
• Less common mechanisms — spontaneous coronary artery dissection (particularly in younger women), coronary spasm, embolism, and MI with non-obstructive coronary arteries.

Symptoms

Typical presentation

• Central chest pain, pressure or tightness, often radiating to the arm, neck, jaw or back.
• Breathlessness, sweating, nausea, vomiting and light-headedness.
• A sense of impending doom, which patients describe consistently and which should be taken seriously.
• Symptoms lasting more than a few minutes and not relieved by rest.

Atypical presentation

Women, older people, those with diabetes and people from some cultural backgrounds frequently present without classic chest pain — with breathlessness, fatigue, nausea, epigastric discomfort, syncope or simply feeling unwell. This is a major cause of delayed presentation and delayed diagnosis, and both patients and clinicians contribute to it.

Symptoms during recovery

In the weeks afterwards, breathlessness on exertion, fatigue, chest wall soreness after surgery, palpitations and poor sleep are all common. Distinguishing normal recovery sensations from recurrent ischaemia is a frequent source of anxiety, and giving people explicit criteria helps more than reassurance.

Warning signs

Diagnosis

Why diagnosis matters

Rapid diagnosis enables emergency reperfusion that saves heart muscle, and determines the MI type — which dictates how quickly the artery must be opened. In STEMI the target is measured in minutes; in NSTEMI, in hours to days according to risk. Getting this classification right within minutes of arrival is the highest-stakes decision in the pathway.¹

How is it diagnosed?

Diagnosis combines the clinical presentation, a 12-lead ECG performed within ten minutes of first medical contact, and high-sensitivity cardiac troponin measured serially. Rapid rule-out algorithms using troponin at presentation and one to three hours later now allow many patients to be safely discharged within hours.

Angiography and imaging

Coronary angiography defines the anatomy and permits immediate treatment with percutaneous coronary intervention. Echocardiography assesses left ventricular function, regional wall motion, valve function and mechanical complications, and is what determines much of the subsequent management. Cardiac MRI is used where the diagnosis is unclear or myocarditis is possible.

Investigations for related conditions

After the event, assessment of left ventricular function, lipids, glucose and glycated haemoglobin, blood pressure, renal function and iron studies guides secondary prevention and identifies those needing device therapy or heart failure treatment. Screening for depression, anxiety and sleep-disordered breathing belongs in this list rather than as an afterthought.

Management

Management and goals

The immediate goal is to restore coronary flow as fast as possible. The subsequent and equally important goals are to limit adverse remodelling, prevent a further event, restore function and confidence, and address the risk factors that produced the first infarct. The second set determines the next twenty years and receives, in practice, a fraction of the attention given to the first.

Emergency reperfusion

Primary percutaneous coronary intervention with stenting is the treatment of choice in STEMI where it can be delivered promptly; fibrinolysis is used where transfer times are long — a live consideration in regional Queensland. Coronary artery bypass grafting is used for extensive or complex disease. In NSTEMI, an early invasive strategy is guided by risk stratification.

Phases of recovery

• Phase 1 (hospital) — stabilisation, early gentle mobilisation, wound care, and education before discharge.
• Early outpatient phase — gradually increasing daily activity, monitoring the access site or sternal wound, and beginning to process what has happened.
• Cardiac rehabilitation (phases 2–3) — supervised exercise and risk-factor modification over 6 to 12 weeks.
• Maintenance (phase 4) — lifelong activity and prevention.

Cardiac rehabilitation

Exercise-based cardiac rehabilitation reduces cardiovascular mortality and hospital admissions and improves health-related quality of life in coronary heart disease, and is recommended for everyone after an MI.² Australian linked-data analysis confirms the benefit in practice: attendance at cardiac rehabilitation and secondary prevention programmes was associated with significantly lower 12-month mortality and readmission.³ Despite this, uptake nationally remains poor — often under half of eligible patients — which makes referral and active follow-up one of the highest-value interventions available. Home-based programmes are a legitimate alternative, with comparable outcomes to centre-based rehabilitation for mortality, cardiac events, exercise capacity and quality of life, which matters considerably for patients in regional areas.⁴

At Inspire Clinic, cardiorespiratory rehabilitation is delivered as individually supervised sessions, with home-based options and remote monitoring where appropriate.

Identifying deterioration

Recurrent chest pain, new or worsening breathlessness, orthopnoea, ankle swelling, palpitations, syncope or a fall in exercise tolerance all warrant prompt review for reinfarction, heart failure, arrhythmia or stent problems. Access-site bleeding or a swelling after angiography needs same-day assessment.

Medications

Secondary prevention medicines

Four groups do the work: dual antiplatelet therapy — aspirin with ticagrelor, prasugrel or clopidogrel — for a defined period, then aspirin indefinitely; a high-intensity statin, with additional lipid-lowering therapy where targets are not met; a beta-blocker; and an ACE inhibitor or angiotensin receptor blocker, particularly where left ventricular function is reduced. An SGLT2 inhibitor and a mineralocorticoid receptor antagonist are added where heart failure or diabetes coexists.

Correct use of medications

Dual antiplatelet therapy must not be stopped early after stenting without cardiology advice — premature cessation carries a real risk of stent thrombosis, which is frequently fatal. Patients should be told this explicitly, carry a card recording their stent and regimen, and know to raise it before any surgery or dental procedure. Statin-related muscle symptoms are common and usually manageable by switching agent or dose rather than stopping. Beta-blockers may cause fatigue and blunt the exercise heart-rate response, which matters for exercise prescription.

Adherence

Adherence to secondary prevention medication falls substantially within the first year, and non-adherence is a stronger predictor of a further event than most clinical variables. Simplifying regimens, using dose administration aids and asking non-judgementally about missed doses achieve more than repeated instruction.

Multi-system manifestations

Heart failure

The commonest late consequence of a large infarct, through adverse remodelling and loss of contractile muscle. Ejection fraction is reassessed after recovery, since it determines eligibility for device therapy and additional pharmacotherapy.

Arrhythmia and sudden death

Ventricular arrhythmia arising from the scar border zone, and atrial fibrillation, both increase in incidence after infarction. Implantable defibrillator assessment is indicated where ejection fraction remains significantly reduced beyond the recovery period.

Kidneys

Contrast-induced and haemodynamic acute kidney injury around the acute event, and chronic kidney disease as both a shared risk factor and a consequence — each constraining drug choice and dosing.

Mental health

Depression affects roughly one in five people after MI and anxiety more still. This is not merely a quality-of-life issue: anxiety after myocardial infarction independently predicts all-cause mortality and influences rehabilitation outcomes.⁵ Screening and treating it is cardiological care.

Skeletal muscle and function

Deconditioning after an acute event is rapid, particularly in older patients, and combines with fear of exertion to produce a functional decline out of proportion to the cardiac damage. This is the component most responsive to rehabilitation.

Sexual function and relationships

Erectile dysfunction is common, both as a marker of vascular disease and as a side effect of treatment, and fear of triggering another event affects both partners. It is rarely raised by patients and should be asked about — sexual activity is generally safe once moderate exertion is tolerated.

Living with the condition

Returning to normal life

Most people return to normal activities, including driving and work, within weeks — individualised to the type of MI, the treatment received, left ventricular function and the demands of the occupation. Driving restrictions after an MI or intervention are specified in national fitness-to-drive standards and differ for commercial licence holders.

Stopping smoking

The single most effective step a person can take. Smoking cessation after MI is associated with a substantial reduction in mortality — a systematic review found around a 36% reduction in all-cause mortality compared with continued smoking, a benefit comparable to or greater than any individual drug.⁶ The admission itself is the most effective moment to intervene, with pharmacotherapy and behavioural support.

Diet, weight and alcohol

A Mediterranean-style pattern, reduced salt and saturated fat, and moderation of alcohol. Dietitian involvement is more effective than advice given in passing, particularly where diabetes coexists.

Staying active for life

Completing rehabilitation is the start rather than the finish. The gains from a 6 to 12-week programme are lost within months without continuation, so the transition to sustainable independent activity is planned as part of the programme, not left to chance.

Mood, sleep and stress

Anxiety about recurrence is near-universal in the early weeks and usually settles. Persistent low mood, avoidance of activity, sleep disturbance or intrusive fear warrants formal assessment and treatment, given the association with outcome.

Recognising another event

Everyone should leave hospital knowing the warning signs, that they must call 000 rather than drive, and what their action plan is. Family members should know it too, since patients frequently delay while others push them to act.

Prognosis

The outlook has improved greatly with prompt reperfusion and secondary prevention, and many people live long, active lives after an MI. Prognosis depends on the amount of myocardium affected, left ventricular function, completeness of revascularisation, control of risk factors, and — to a degree that is consistently under-appreciated — whether the person completes rehabilitation, takes their prevention medicines and stops smoking. Those three behavioural factors together have an effect on survival comparable to the acute intervention itself, which reframes the weeks after discharge as an active treatment period rather than convalescence.

Role of the physiotherapist

Physiotherapy delivers the exercise component of cardiac rehabilitation, which is the intervention with the strongest evidence for improving survival and quality of life after MI.

Assessment and prescription begin with a functional baseline — typically a six-minute walk or symptom-limited exercise test — and produce an individualised aerobic and resistance programme. Intensity is a genuine clinical judgement, and the evidence is reassuring: in a large registry of coronary patients undertaking supervised exercise, the rate of cardiovascular events during high-intensity interval training was very low and comparable to moderate-intensity training, supporting higher intensities in appropriately selected, supervised patients.⁷ Progressive resistance training is not an optional extra either: added to aerobic training it improves both strength and aerobic fitness in coronary heart disease more than aerobic training alone.⁸

Monitoring and safety during sessions — symptoms, rating of perceived exertion, heart rate and rhythm, blood pressure response — and recognising abnormal responses that need escalation. Beta-blockade blunts the heart-rate response, so perceived exertion and the talk test are more useful guides than target heart rates.

Restoring confidence is arguably the largest contribution. Many patients are frightened of their own heart rate and quietly avoid exertion; supervised, graded, monitored exercise that demonstrably does no harm is what breaks that. After cardiac surgery, physiotherapy also covers respiratory care, sternal precautions and safe movement, shoulder and thoracic mobility, and wound-aware progression. Throughout, breathing techniques and pacing help with the breathlessness and anxiety that so often follow a cardiac event — and because physiotherapists see these patients weekly for months, they are frequently the first to notice the returning symptoms, the falling exercise tolerance or the low mood that needs acting on.

Part 1 · References

1. Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC guidelines for the management of acute coronary syndromes. Eur Heart J 2023;44(38):3720–3826.
2. Dibben GO, Faulkner J, Oldridge N, et al. Exercise-based cardiac rehabilitation for coronary heart disease. Cochrane Database Syst Rev 2021;(11):CD001800.
3. Astley CM, Chew DP, Keech W, et al. The impact of cardiac rehabilitation and secondary prevention programs on 12-month clinical outcomes: a linked data analysis. Heart Lung Circ 2020;29(3):475–482.
4. Anderson L, Sharp GA, Norton RJ, et al. Home-based versus centre-based cardiac rehabilitation. Cochrane Database Syst Rev 2017;(6):CD007130.
5. Meyer T, Buss U, Herrmann-Lingen C. Role of cardiac disease severity in the predictive value of anxiety for all-cause mortality and exercise-based rehabilitation outcomes after myocardial infarction. Psychosom Med 2010;72(1):9–15.
6. Critchley JA, Capewell S. Mortality risk reduction associated with smoking cessation in patients with coronary heart disease: a systematic review. JAMA 2003;290(1):86–97.
7. Rognmo Ø, Moholdt T, Bakken H, et al. Cardiovascular risk of high- versus moderate-intensity aerobic exercise in coronary heart disease patients. Circulation 2012;126(12):1436–1440.
8. Hollings M, Mavros Y, Freeston J, Fiatarone Singh M. The effect of progressive resistance training on aerobic fitness and strength in adults with coronary heart disease: a systematic review and meta-analysis. Eur J Prev Cardiol 2017;24(12):1242–1259.

References are numbered in citation order (Vancouver/BMJ style) and were current at the time of writing. Guidelines are living documents — verify against the latest version before clinical use.