An introduction to high-resolution ECG recordings of cardiac late potentials

High-resolution electrocardiography utilizes computer processing to record low-levels signals not normally observed on standard electrocardiographs. Cardiac late potentials occur at the end of or after the QRS complex and require these methods to be quantified. A brief overview of the methods used to record late potentials is presented. These include lead placement, computer-implemented signal averaging, high-pass filtering, and feature extraction for characterizing the late potential. The major application of late- potential analysis has been in patients after myocardial infarction. Several of these studies are reviewed that demonstrate the usefulness of this new approach in identifying those patients at greatest risk for developing ventricular tachycardia. The most impressive studies have been those that compare late potentials with measures of ventricular performance and ventricular ectopy.