Other Systemic Causes
Some illnesses outside the heart can look like a heart attack: chest pain, ECG changes and a rise in troponin (a heart-injury blood test). These are mimics — the arteries aren’t suddenly neccessarily blocked, and treatment focuses on the underlying illness rather than stents.
1) Why do systemic illnesses mimic a heart attack?
Serious infections, very low blood count, kidney problems, severe blood-pressure changes and abnormal heart rhythms can all strain the heart. That strain can injure heart muscle and raise troponin, sometimes with chest discomfort and ECG changes. This overlaps with a true heart attack, but the cause is different.
Key idea: a raised troponin means the heart is stressed or injured — it doesn’t always mean a blocked artery.
2) Sepsis and serious infection
Infection can lower blood pressure, speed up the heart and trigger body-wide inflammation. Together these can injure the heart and raise troponin.
Investigations
- Blood tests (inflammation markers, cultures) & troponin
- ECG and chest x-ray as needed
- Echocardiogram to check heart pumping
Treatment
- Prompt antibiotics and fluids
- Oxygen; blood-pressure support if required
- Heart medicines are supportive, based on symptoms
Outlook
- Depends on infection source and severity
- Heart function usually recovers; follow-up can help
3) Severe anaemia (very low blood count)
Low haemoglobin means less oxygen is carried to the heart. The heart works harder and can become sore or injured.
Investigations
- Full blood count and iron/B12/folate tests
- ECG; echo if symptoms persist
- Look for bleeding or other causes
Treatment
- Blood transfusion in severe cases
- Iron/B12/folate replacement
- Treat the underlying cause (e.g., bleeding)
Outlook
- Good once corrected
- Prevent recurrence by fixing the cause
4) Kidney problems (renal impairment)
Kidney disease can raise troponin both from reduced clearance (it stays in the blood longer) and ongoing strain on the heart. Chest discomfort and ECG changes can occur for many reasons in this context.
Investigations
- Kidney function and electrolyte tests
- ECG; echo; consider CMR if needed
- Review medicines and fluid balance
Treatment
- Optimise kidney care and fluids
- Careful use of heart medicines
- Address blood pressure and anaemia
Outlook
- Depends on kidney function
- Cardiovascular follow-up is important
5) Blood-pressure extremes
Very high blood pressure makes the heart work against a higher load; very low blood pressure reduces blood flow to the heart. Either can injure the heart and raise troponin.
Investigations
- BP monitoring; ECG; troponin
- Eye exam (fundoscopy) in hypertensive crises
- Echo or CMR if needed
Treatment & outlook
- Careful BP lowering if very high
- Fluids/medication support if very low
- Good control usually improves symptoms and risk
6) Abnormal heart rhythms (arrhythmias)
Fast rhythms (e.g., atrial fibrillation with a rapid rate) or very slow rhythms can upset the balance between oxygen supply and demand in the heart, causing chest symptoms and a troponin rise.
Investigations
- ECG and rhythm monitoring
- Blood tests (thyroid, electrolytes)
- Echo if symptoms or reduced function
Treatment
- Rate or rhythm control medicines
- Anticoagulation in atrial fibrillation (stroke prevention)
- Pacemaker in selected slow-rhythm cases
Outlook
- Usually good with effective control
- Cardiac rehab supports recovery and confidence
7) Knowledge gaps
- Better ways to tell “heart strain/injury” from a true heart attack at first assessment
- Clearer guidance on when to use or avoid antiplatelets in systemic illness-related troponin rises
- Standard rehab and follow-up pathways for non-coronary causes of troponin elevation
- Recognising and supporting the emotional impact of an uncertain diagnosis
Research & support
Learn more in our research hub and connect with others in the community forum. If your diagnosis is uncertain, ask your team whether a cardiac MRI (CMR) or targeted tests would help.