Summary Electrodiagram Study Notes 2024/2025

ECG  History of the ECG.  Orientation of leads  Information obtained from an ECG  ECG paper  Anatomy of the heart  ECG interpretation 1. History The ECG has been in use for over a century. A British physiologist, Augustus Waller, performed the first ECG recording in 1887, and he gave demonstrations of his technique, using his dog, Jimmy, as the “patient”. Einthoven, from Holland, was present at such a demonstration. Willem Einthoven constructed his well-known triangle and the hexaxial system to help us gain further insight into the electrical activity of the heart. 2. Information obtainable from an ECG ECGs can give us much information about the heart and also give us clues about other aspects of an individual’s state of health, such as: Rhythm – sinus/non-sinus Conduction – normal/abnormal Size of heart chambers Presence of ischaemic heart disease Pulmonary embolism Inflammation of the pericardium/effusion Emphysema Drugs the patient may be on e.g. Digoxin, Calcium channel blockers Electrolyte status of the patient – potassium, calcium levels Temperature – pyrexia or hypothermia Endocrine status – AF in thyrotoxicosis; bradycardia in hypothyroidism Raised intracranial pressure In ischaemic heart disease, the ECG may give us several pieces of information, such as: • The location of the affected area of myocardium (in order of frequency) Antero-septal area Inferior surface of the heart Antero-lateral aspect of the left ventricle etc •Whether the full thickness of the ventricular wall or only part of it is involve