What are the indications for referring a patient with abnormal ECG findings to a cardiologist?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 21 August 2025Updated: 21 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Referral to a cardiologist for abnormal electrocardiogram (ECG) findings is indicated in several scenarios, particularly when associated with specific clinical presentations or concerning ECG patterns.

  • Urgent Cardiovascular Assessment (within 24 hours) for Transient Loss of Consciousness (TLoC): An urgent referral for cardiovascular assessment, to be reviewed and prioritised by an appropriate specialist within 24 hours, is required for anyone with TLoC who also has an ECG abnormality . ECG abnormalities considered red flags in this context include:
    • Conduction abnormalities (e.g., complete right or left bundle branch block, or any degree of heart block) .
    • Evidence of a long QT interval (corrected QT more than 450 ms) or a short QT interval (corrected QT less than 350 ms) .
    • Any ST segment or T wave abnormalities .
    • Inappropriate persistent bradycardia .
    • Any ventricular arrhythmia (including ventricular ectopic beats) .
    • Brugada syndrome .
    • Ventricular pre-excitation (part of Wolff-Parkinson-White syndrome) .
    • Left or right ventricular hypertrophy .
    • Abnormal T wave inversion .
    • Pathological Q waves .
    • Sustained atrial arrhythmia .
    • Paced rhythm .
  • Suspected Acute Coronary Syndrome (ACS): ECG findings suggestive of ACS necessitate immediate management and typically involve hospital transfer for specialist care:
    • Regional ST-segment elevation or presumed new left bundle branch block (LBBB) consistent with an acute ST-elevation myocardial infarction (STEMI) .
    • Regional ST-segment depression or deep T wave inversion suggestive of a non-ST-elevation myocardial infarction (NSTEMI) or unstable angina .
    • Other changes such as Q waves and T wave changes, if an ACS is suspected .
  • Suspected Heart Valve Disease: An echocardiogram should be offered to adults with a heart murmur if valve disease is suspected and they have an abnormal ECG, especially if accompanied by signs (such as peripheral oedema) or symptoms (such as angina or breathlessness) . This investigation often precedes or is part of a specialist cardiology assessment .

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