12-lead ECG interpretation and chest pain management: 1

Using the 12-lead ECG to assess acute coronary patients

Acute coronary syndromes (ACS) are characterized by the rupture of unstable plaque within coronary arteries. Depending on the extent of the ensuing occlusion and myocardial damage, ACS can be classified as unstable angina, non-ST elevation myocardial infarction (MI) and ST elevation MI. The electrocardiogram (ECG) is an invaluable tool in the assessment of patients with ACS. It provides evidence for the location of myocardial ischaemia, injury and infarction and is a crucial factor in the decision to administer thrombolytic agents and other management strategies. The 12-lead ECG is limited to a view of the left ventricle, however it can be extended to provide additional information about the right ventricular and posterior walls. Critical care nurses with ECG skills can contribute to the early detection and management of patients with ACS.

Clinical skills: the physiological basis and interpretation of the ECG

Electrocardiograph (ECG) interpretation is a complex subject that requires considerable experience. However, an understanding of the principles underlying generation of the ECG can make this learning process easier. This knowledge is necessary if interpretation is to be founded on understanding rather than being a pattern recognition-based process. The aim of this article is to introduce the practitioner to the basic processes and mechanisms that govern formation of the normal ECG. These principles will largely be applied to the normal ECG and include cardiac anatomy applied to the ECG, how the ECG leads look at the heart and how the normal ECG waveform is formed. Examples of how the ECG changes when the underlying mechanisms are disturbed will also be given. Together, this knowledge should help the practitioner to have a clearer understanding of interpreting the abnormalities seen on an ECG.