Until about 2003, the only available portion of the AHA database consisted of 80 two-channel excerpts of analog ambulatory ECG recordings, digitized at 250 Hz per channel with 12-bit resolution over a 10 mV range. These 80 recordings, designated as the development set or series 1, are divided into eight classes of ten recordings each, according to the highest level of ventricular ectopy present:
- no ventricular ectopy (records 1001 through 1010)
- isolated unifocal PVCs (records 2001 through 2010)
- isolated multifocal PVCs (records 3001 through 3010)
- ventricular bi- and trigeminy (records 4001 through 4010)
- R-on-T PVCs (records 5001 through 5010)
- ventricular couplets (records 6001 through 6010)
- ventricular tachycardia (records 7001 through 7010)
- ventricular flutter/fibrillation (records 8001 through 8010)
無心室異位（記錄1001至1010）
孤立的單竈性pvc（2001年至2010年的記錄）
孤立的多竈pvc（記錄3001到3010）
室性早搏二聯律和三聯律（記錄4001到4010）
R-on-T PVCs（記錄5001至5010）
成對室早（記錄6001至6010）
室性心動過速（記錄7001至7010）
心室撲動/顫動（記錄8001至8010）