Heart Attack Misdiagnosis Claims: When a Missed MI Is Negligence

Why are heart attacks misdiagnosed?

Myocardial infarction does not always present with crushing central chest pain radiating to the left arm. Atypical presentations — particularly in women, younger patients, and people with diabetes — are a significant source of missed diagnoses. Common atypical presentations include:

• Jaw or back pain without chest pain
• Breathlessness as the primary symptom
• Nausea and abdominal pain mistaken for gastrointestinal illness
• Fatigue without chest pain in women
• Heartburn-type symptoms

Clinicians assessing chest pain are expected to consider and exclude cardiac causes before attributing symptoms to non-cardiac causes. Cardiac risk factors (hypertension, diabetes, hypercholesterolaemia, smoking, family history) must be taken into account.

What are the clinical standards for chest pain assessment?

NICE guidance (NG185) and cardiology standards require:

• A 12-lead ECG performed within 10 minutes of first clinical assessment for patients with chest pain
• Troponin levels measured at presentation and again at 3 hours (high-sensitivity troponin assays) to rule in or rule out acute MI
• STEMI patients sent immediately to a cardiac catheterisation laboratory for PPCI
• NSTEMI patients risk-stratified and treated with anticoagulation and early intervention

Failure to perform an ECG, to measure troponin, to correctly interpret ECG findings, or to refer a STEMI patient urgently for PPCI are all potential bases for a claim where they cause harm.

What are common scenarios in heart attack misdiagnosis claims?

Atypical MI sent home from A&E

A patient (often a woman or a patient with diabetes) presents with breathlessness, nausea, or jaw pain. A chest infection or gastrointestinal cause is assumed. An ECG is not performed or is misread. Troponin is not checked. The patient is sent home and suffers a major MI or cardiac arrest.

ECG misreported by GP or A&E clinician

An ECG showing ST-elevation or new left bundle branch block — both indicating STEMI — is not recognised by the reading clinician. The patient is not transferred urgently to a cardiac centre.

NSTEMI discharged without treatment

A patient with an NSTEMI — shown by elevated troponin — is discharged without anticoagulation or early angiography referral. They suffer further myocardial damage or a subsequent MI that appropriate treatment would have prevented.

Out-of-hours telephone triage failure

A patient calls 111 or an out-of-hours service with chest pain. The triage system does not identify the call as a potential cardiac emergency. The patient is advised to see a GP the next day and deteriorates overnight.

What do you need to prove?

1. Duty of care — the clinician owed a duty to assess and treat you competently.
2. Breach of duty — the failure to diagnose or treat the MI fell below the standard of a reasonably competent clinician. An independent cardiology expert will assess this.
3. Causation — the delay caused additional myocardial damage or death beyond what timely treatment would have caused.
4. Damage — reduced cardiac function, heart failure, permanent disability, or death.

How much compensation can you claim for a missed heart attack?

Compensation depends on the degree of additional cardiac damage caused by the missed diagnosis. A delay causing a modest reduction in left ventricular function may result in a moderate award. Where the missed MI causes severe heart failure, inability to work, or death, compensation including future care and dependency can be substantial.

Frequently asked questions

Related guides

• Medical negligence claims — complete guide
• A&E negligence claims
• Misdiagnosis claims
• Compensation after a death from medical negligence