Annotations in the MIT-BIH Malignant Ventricular Fibrillation Database

All of the annotations contained in the .atr files of this database are rhythm change annotations, and almost all of them mark changes in cardiac rhythm (a few indicate episodes of noise or asystole). The table below indicates how the aux strings of these annotations should be interpreted.

aux stringMeaning
(AFIBatrial fibrillation
(Bventricular bigeminy
(BIfirst degree heart block
(HGEAhigh grade ventricular ectopic activity
(N or (NSRnormal sinus rhythm
(NODnodal ("AV junctional") rhythm
(PMpacemaker (paced rhythm)
(SBRsinus bradycardia
(SVTAsupraventricular tachyarrhythmia
(VERventricular escape rhythm
(VF or (VFIBventricular fibrillation
(VFLventricular flutter
(VTventricular tachycardia

In each case, the rhythm change annotations are placed at the beginning of the episode of the indicated rhythm. The previous rhythm continues during episodes marked by (NOISE; the noise ends at the time of the next annotation.