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

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 ¹. 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) ¹.
  • Evidence of a long QT interval (corrected QT more than 450 ms) or a short QT interval (corrected QT less than 350 ms) ¹.
  • Any ST segment or T wave abnormalities ¹.
  • Inappropriate persistent bradycardia ¹.
  • Any ventricular arrhythmia (including ventricular ectopic beats) ¹.
  • Brugada syndrome ¹.
  • Ventricular pre-excitation (part of Wolff-Parkinson-White syndrome) ¹.
  • Left or right ventricular hypertrophy ¹.
  • Abnormal T wave inversion ¹.
  • Pathological Q waves ¹.
  • Sustained atrial arrhythmia ¹.
  • Paced rhythm ¹.
• 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) ³.
  • Regional ST-segment depression or deep T wave inversion suggestive of a non-ST-elevation myocardial infarction (NSTEMI) or unstable angina ³.
  • Other changes such as Q waves and T wave changes, if an ACS is suspected ³.
• 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) ². This investigation often precedes or is part of a specialist cardiology assessment ².