The standard 12-lead electrocardiogram (ECG) is one of the most commonly used methods for diagnosing heart disease. Standard ECG is not always optimal, however, and new ECG methods can provide additional information. Analysis of high-frequency QRS components (HF-QRS) has been shown to increase the diagnostic performance of the ECG. Several investigators have studied HF-QRS in different cardiac conditions, including acute myocardial ischaemia and myocardial infarction, but more knowledge is needed about the characteristics of HF-QRS before clinicians can use it as an adjunct to standard ECG.