The need for computer-based ventricular arrhythmia detectors (VADs) has been accentuated recently by studies of arrhythmic deaths and by the increasing use of Holter-tape recordings for a variety of other research applications. In order to facilitate the assessment of VAD performance and the comparison of VAD evaluation results, the establishment of a standardized ECG database for VAD development and evaluation has been proposed and funded. This database, to be collected by Washington University under the supervision of the American Heart Association (AHA) acting through its Committee on Electrocardiography, will be obtained primarily from Holter tapes recorded as part of research studies at Washington Univeristy and several other institutions. A Selection Committee appointed by the AHA and made up of scientists from several separate institutions will have responsibility for final database contents. The AHA will also appoint a panel of expert electrocardiographers to annotate the database on a beat-by-beat basis.