ECG diagnosis of acute ischaemia and infarction: past, present and future

Abstract

A century has passed since Einthoven published his description of the human electrocardiogram (ECG), recorded using a string galvanometer. The basic principles of this technique have remained unchanged, and it has revolutionized the diagnosis and management of cardiac pathology. At present, its sensitivity in diagnosing life-threatening myocardial infarction and ischaemia is inferior to that of biochemical markers. However, the ECG monitors cardiac function in real time, while biochemical assays can delay the diagnosis of acute myocardial infarction (AMI) and treatments that need to be delivered promptly. We review the historical development of the ECG and its limitations as a diagnostic tool for AMI, and highlight recent research into higher-resolution technologies for real-time cardiac monitoring, and how they may impact on chest pain management. Many distinguished scientists and clinicians have devoted their life's work to the use and understanding of the technique. This short review will merely highlight some of the more important contributions. The electrical activity of the heart was an incidental finding of Kolliker and Muller in 1856. 1 When a frog sciatic nerve/gastrocenemius preparation fell onto an isolated frog heart, both muscles contracted synchronously, suggesting that the heart generates electrical impulses. This activity was directly recorded and visualized using a Lippmann capillary electrometer by the British physiologist John Burdon Sanderson. 2 In 1887, Augustus Desire Waller used this technique to show that cardiac electrical potentials could be recorded via the limbs and directly from the chest of intact animals and humans. 3 The electrical activity preceded the heart's contraction, excluding an artefact caused by ‘a mechanical alteration of contact between the electrodes of the chest wall caused by the heart's impulse’. However, the clinical importance of his recordings was overlooked. Inspired by a demonstration by Waller, the Dutch physiologist Willem Einthoven began to develop capillary electrometer technology. This … Address correspondence to Dr N. Herring, Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Sherrington Building, Parks Road, Oxford OX1 3PT. email: neilherring{at}doctors.org.uk