Missed ECG Findings: Common Errors in Cardiac Negligence Claims

In cardiology medico-legal practice, electrocardiogram (ECG) interpretation is a frequent source of dispute in clinical negligence claims. The ECG remains a cornerstone of cardiac assessment, particularly in acute settings where timely recognition of myocardial infarction (MI) can significantly alter outcomes. When ECG findings are allegedly missed or misinterpreted, the legal consequences can be profound, potentially engaging liability under the principles established in Bolam v Friern Hospital Management Committee [1957] and refined in Bolitho v City and Hackney Health Authority [1998]. This article examines the most common ECG-related errors in cardiac negligence claims, their clinical and legal frameworks, and the pivotal role of the expert witness in such cases.

Clinical Context: ECG Interpretation in Acute Cardiac Care

The ECG is a fundamental tool in the evaluation of chest pain, syncope, and other presentations suggestive of acute coronary syndromes (ACS). Current NICE guidance (NG185) on acute coronary syndromes emphasises the importance of early ECG acquisition and interpretation, ideally within ten minutes of first medical contact for patients with suspected ST-elevation myocardial infarction (STEMI). However, the subtleties of ECG interpretation can pose challenges even for experienced clinicians.

Key ECG patterns that frequently feature in medico-legal disputes include:

• Subtle STEMI: ST-elevation may be minimal or confined to specific leads (e.g., inferior or posterior), particularly in early presentations. Posterior MI, for instance, may only manifest as reciprocal ST-depression in anterior leads, which can be overlooked if not actively sought.
• De Winter T-waves: Characterised by upsloping ST-depression with hyperacute T-waves in precordial leads, this pattern is often misinterpreted as non-specific ischaemia rather than a STEMI equivalent.
• Wellens syndrome: Biphasic or deeply inverted T-waves in anterior leads, indicative of critical left anterior descending artery stenosis. This pattern is frequently missed in patients with resolving chest pain, leading to inappropriate discharge.
• Left bundle branch block (LBBB): The Sgarbossa criteria are essential for identifying acute MI in the presence of LBBB, yet these criteria are not universally applied in clinical practice.
• Right ventricular infarction: ST-elevation in lead V1 or right-sided leads (V3R-V6R) may be absent or overlooked, particularly if right-sided leads are not routinely recorded.

High-sensitivity troponin assays have transformed the diagnostic pathway for ACS, but their interpretation must be contextualised with ECG findings. The Fourth Universal Definition of MI underscores the importance of integrating ECG changes with clinical presentation and biomarker trends. In medico-legal cases, disputes often arise when troponin results are interpreted in isolation, without due consideration of the ECG or the patient’s pre-test probability of ACS.

Legal Relevance: Breach of Duty and Causation

In cardiac negligence claims, the legal analysis typically centres on two key questions: whether there was a breach of duty in ECG interpretation, and whether any such breach caused or materially contributed to the claimant’s harm. The Bolam test remains the starting point for assessing breach of duty, requiring that the clinician’s actions be judged against the standard of a responsible body of medical opinion. However, the Bolitho refinement demands that such opinion must also be capable of withstanding logical analysis, particularly where the alleged breach involves a failure to recognise a well-established clinical pattern.

Causation in ECG-related claims is often complex. The courts have grappled with issues of material contribution (Bailey v Ministry of Defence [2008]) and the loss of a chance (Gregg v Scott [2005]) in cases where timely intervention might have altered the outcome. For example, in a claim involving a missed STEMI, the expert witness may be asked to opine on whether earlier reperfusion therapy would have preserved myocardial function, reduced infarct size, or prevented complications such as heart failure or arrhythmia. Such assessments require a nuanced understanding of the time-dependent benefits of interventions like percutaneous coronary intervention (PCI) or thrombolysis, as well as the natural history of untreated MI.

The Montgomery v Lanarkshire Health Board [2015] judgment has also influenced the duty of care in cases where ECG findings are ambiguous. Clinicians are now expected to engage in a dialogue with patients about the risks and benefits of further investigation or treatment, particularly where the ECG suggests a potential but not definitive diagnosis of ACS. Failure to communicate such uncertainties may itself give rise to a claim, even if the ECG interpretation was technically correct.

Common Pitfalls and Disputes in ECG-Related Claims

Several recurring themes emerge in ECG-related clinical negligence claims:

1. Over-reliance on Computerised Interpretation

Modern ECG machines provide automated interpretations, which can be a useful adjunct but are not infallible. In medico-legal practice, experts frequently encounter cases where clinicians have deferred to the computerised report without applying their own clinical judgment. This is particularly problematic in subtle patterns such as de Winter T-waves or Wellens syndrome, where automated systems may label the ECG as “non-specific” or “normal”. The Bolam test does not absolve clinicians of their duty to critically appraise automated reports, and experts may be asked to comment on whether such reliance constitutes a breach of duty.

2. Failure to Repeat ECGs

ECG changes can evolve rapidly in ACS, and a single “normal” ECG does not exclude the diagnosis. NICE guidance (NG185) recommends repeating the ECG if the initial tracing is non-diagnostic but clinical suspicion remains high. Claims often arise when a patient is discharged after a single ECG, only to suffer a subsequent event. Experts may be asked to assess whether the decision not to repeat the ECG was defensible, or whether it fell below the standard expected of a reasonably competent clinician.

3. Misinterpretation of Non-Specific Changes

Non-specific ST-segment or T-wave changes are a frequent source of dispute. While such findings may be benign, they can also represent early ischaemia or other pathology. In medico-legal cases, experts are often asked to opine on whether the clinician’s interpretation of such changes was reasonable, or whether further investigation (e.g., serial ECGs, troponin testing, or referral to cardiology) should have been undertaken. The Bolitho test may be particularly relevant here, as the expert must assess whether the clinician’s decision-making process was logical and defensible.

4. Contextual Factors in ECG Interpretation

The interpretation of an ECG cannot be divorced from the clinical context. For example, an ECG showing ST-elevation in a young patient with chest pain may be more likely to represent pericarditis than STEMI, whereas the same ECG in an older patient with risk factors would warrant urgent reperfusion therapy. Claims may arise when clinicians fail to integrate the ECG findings with the patient’s history, examination, and risk profile. Experts may be asked to comment on whether the clinician’s interpretation was reasonable given the available clinical information.

5. Documentation and Communication Failures

Inadequate documentation of ECG findings, or failures in communicating those findings to other members of the clinical team, can also give rise to claims. For example, if an ECG is performed in primary care and shows concerning features, but the report is not clearly documented or communicated to the patient, this may constitute a breach of duty. Similarly, in hospital settings, failures to escalate abnormal ECG findings to senior clinicians or cardiology teams can lead to delays in treatment. Experts may be asked to assess whether the documentation and communication practices in a given case met the expected standard of care.

The Role of the Expert Witness in ECG-Related Claims

Expert witnesses play a critical role in ECG-related clinical negligence claims, providing independent, CPR Part 35-compliant opinions on breach of duty and causation. The expert’s role extends beyond simply reviewing the ECG; they must also consider the broader clinical context, the applicable guidelines, and the legal tests that the court will apply.

Breach of Duty Assessment

In assessing breach of duty, the expert must evaluate whether the clinician’s interpretation of the ECG was reasonable, applying the Bolam and Bolitho tests. This involves:

• Reviewing the ECG in question, ideally with access to the original tracing rather than a printed report.
• Considering the clinical context, including the patient’s history, examination findings, and risk factors.
• Assessing whether the clinician’s interpretation aligns with current guidelines (e.g., NICE NG185, ESC guidelines on ACS).
• Evaluating whether the clinician’s decision-making process was logical and defensible, particularly in cases involving subtle or ambiguous ECG findings.

The expert must also consider whether the clinician’s actions (or inactions) were consistent with the standard of care expected of a reasonably competent practitioner in the same specialty. For example, if a junior doctor in the emergency department misinterprets an ECG, the expert may be asked to comment on whether this reflects a systemic failure in training or supervision, rather than an individual error.

Causation Assessment

Assessing causation in ECG-related claims often requires the expert to address complex clinical questions, such as:

• Would earlier recognition of the ECG findings have led to a different clinical outcome?
• If reperfusion therapy had been administered sooner, would this have preserved myocardial function or prevented complications?
• Did the delay in diagnosis materially contribute to the claimant’s harm, or would the outcome have been the same regardless?

These questions demand a detailed understanding of the pathophysiology of ACS, the time-dependent benefits of interventions, and the natural history of untreated MI. The expert must also be familiar with the legal principles governing causation, including the Bailey test for material contribution and the Gregg v Scott principles on loss of a chance.

Report Writing and Joint Statements

A CPR Part 35-compliant expert report in an ECG-related claim must be clear, concise, and focused on the legal issues at hand. The report should:

• Provide a detailed analysis of the ECG findings, including any relevant measurements (e.g., ST-segment elevation, Q-wave depth).
• Explain the clinical significance of the ECG changes, with reference to current guidelines and the patient’s presentation.
• Assess whether the clinician’s interpretation was reasonable, applying the Bolam and Bolitho tests.
• Address the question of causation, with reference to the specific harm alleged by the claimant.
• Highlight any systemic issues that may have contributed to the alleged breach, such as training deficits or resource constraints.

In cases where joint expert statements are required, the expert must engage constructively with their counterpart, focusing on areas of agreement and disagreement. The joint statement process is an opportunity to clarify the key issues for the court, and the expert must ensure that their opinions are presented in a manner that is both clinically accurate and legally relevant.

Practical Guidance for Solicitors

For solicitors handling ECG-related clinical negligence claims, early instruction of a specialist cardiology expert witness is pivotal. Key considerations include:

1. Timing of Expert Instruction

Instructing an expert early in the claim process allows for a thorough review of the medical records, including the original ECG tracings. This can help identify potential breaches of duty or causation issues at an early stage, informing the decision to proceed with the claim.

2. Selection of the Expert

ECG interpretation is a subspecialty within cardiology, and not all cardiologists will have the same level of expertise in this area. Solicitors should seek experts with:

• Current or recent clinical practice in acute cardiology, with experience in interpreting ECGs in high-pressure settings (e.g., emergency departments, coronary care units).
• A track record of providing expert evidence in ECG-related claims, with familiarity with the legal tests for breach of duty and causation.
• Knowledge of current guidelines (e.g., NICE NG185, ESC guidelines on ACS) and their application in clinical practice.

3. Focus on the Legal Issues

The expert’s role is to assist the court, not to advocate for either party. Solicitors should ensure that the expert’s instructions are focused on the legal issues in the case, such as:

• Whether the clinician’s interpretation of the ECG was reasonable, applying the Bolam and Bolitho tests.
• Whether any breach of duty caused or materially contributed to the claimant’s harm.
• Whether the claimant’s outcome would have been different if the ECG findings had been recognised and acted upon sooner.

Conclusion

Missed or misinterpreted ECG findings are a recurring theme in cardiac negligence claims, with significant legal and clinical implications. The subtleties of ECG interpretation, combined with the time-critical nature of acute cardiac care, create a fertile ground for disputes over breach of duty and causation. For solicitors handling such claims, early instruction of a specialist cardiology expert witness can provide invaluable insights into the clinical and legal issues at stake.

Expert witnesses in this field must combine clinical expertise with a thorough understanding of the legal framework, including the Bolam, Bolitho, and Montgomery tests. Their role is not merely to interpret the ECG, but to contextualise the findings within the broader clinical picture, assess the reasonableness of the clinician’s actions, and address the complex question of causation. By doing so, they can assist the court in reaching a fair and informed decision, while also helping solicitors to navigate the complexities of ECG-related claims.