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This database includes 35 eight-minute ECG recordings of human subjects who experienced episodes of sustained ventricular tachycardia, ventricular flutter, and ventricular fibrillation.
Record cu01 was obtained from a long-term ECG (Holter) recording (played back at real time for digitization); the other records were digitized in real time from high-level (1 V/mV nominal) analog signals from patient monitors. All signals were passed through an active second-order Bessel low-pass filter with a cutoff of 70 Hz, and were digitized at 250 Hz with 12-bit resolution over a 10 V range (10 mV nominal relative to the unamplified signals). Each record contains 127,232 samples (slightly less than 8.5 minutes).
In episodes of cardiac failure, fibrillation is almost always preceded by a run of ventricular tachycardia, which eventually gives way to the fibrillation itself. The onset of fibrillation is extremely difficult to pinpoint in many cases. Any clinically useful detector should respond to the runs of tachycardia preceding fibrillation, since medical intervention is needed at the earliest opportunity. Thus any detector responding to the premonitory tachycardia can exhibit a negative “time to alarm” compared to the onset of fibrillation as recorded in the reference annotation files. For this reason, the database is defined as a tachyarrhythmia database rather than a fibrillation database.
In these records, the minimum number of non-VF beats prior to the onset of a VF episode is 61. The mean time interval from the beginning of the record to the onset of VF is 5:47 (with a standard deviation of 2:01). Five records (cu12, cu15, cu24, cu25, and cu32) were from paced patients (in some cases, pacing artifacts are not visible, and pacing is apparent only from the regularity of the rhythm). Repeated defibrillation attempts are visible in many records.
The recordings were originally collected by Floyd M. Nolle at the Creighton University Cardiac Center. High-quality recordings of these rhythms are extremely rare, and of great importance both for development and evaluation of VF detectors and for basic research on the dynamics of VF. We wish to thank Richard W. Bowser, formerly of the Creighton University Cardiac Center, for preserving these recordings, for making them available for distribution in this format, and for preparing the preceding notes on this database.
The reference annotation files supplied for this database have been included to aid users in locating events of interest. They are in no sense definitive. All beats are labelled normal (although many are ectopic). VF onset annotations mark only the approximate beginnings of VF episodes.
The reference annotation files for records cu01, cu03, and cu12 were updated in January 2006 to include previously missing ventricular fibrillation onset and end annotations (thanks to Janusz Irzyk for reporting these missing). The previous versions of these three files remain available here for comparison (cu01.atr-, cu03.atr-, and cu12.atr-).