12-Lead ECG Interpretation

A 12-lead ECG is a time-stamped map of cardiac electrical activity. Its value depends on what the tracing shows, when it was obtained, whether it is changing, and how it fits the patient’s symptoms and haemodynamic state. The advanced interpreter does not treat an isolated wave as a diagnosis; the task is to recognize acute coronary occlusion, dangerous conduction or repolarization abnormalities, metabolic effects, and stable baseline variants quickly enough to change the outcome. In suspected acute coronary syndrome, obtain the ECG and arrange qualified clinical interpretation within 10 minutes of first medical contact or emergency-department arrival. A technically adequate but unread tracing has not completed the time-critical assessment. In Canada, authority for ECG acquisition, independent interpretation, code activation, and protocol-initiated interventions is determined by the applicable provincial regulator, employer policy, and medical directive. Practise within the authorization and competence of your setting, while escalating immediately when the tracing and clinical picture suggest an emergency.