IDENTIFICATION OF ATRIAL-FIBRILLATION EPISODES IN AMBULATORY ELECTROCARDIOGRAPHIC RECORDINGS - VALIDATION OF A METHOD FOR OBTAINING LABELEDR-R INTERVAL FILES

Current systems for analyzing ambulatory electrocardiograms (ECGs) are unable to distinguish precisely between sinus rhythm and atrial fibri llation (AF) episodes, and are unable to produce RR interval listings that distinguish AF from sinus rhythm on a beat-to-beat basis. We desc ribe a method for obtaining such a computerized listing (''Composite R hythm'' file) from ambulatory recordings containing episodes of AF. Th e file lists the rhythm of each beat, its real time, and the QRS compl ex morphology. A visual inspection is made of a full printout of the r ecording to identify the precise time of onset and termination of each episode of AF. These times are entered into a computer and identified with the corresponding beats on a conventional RR interval file gener ated by Holter analysis. The method was validated using 1-hour segment s from 20 ambulatory ECGs containing 145 episodes of AF. These were vi sually identified by four independent observers with a mean sensitivit y of 99.1%. The first beat of AF was identified concordantly in 96% of episodes, with a discrepancy of less than or equal to 3 beats in the other episodes. The times of 200 selected QRS complexes were then ente red into the computer by each observer; 91.1% of these complexes were identified exactly and 100% were identified to within one beat. The Co mposite Rhythm files have several potential applications for testing A F detection algorithms and studying the mode of onset of AF.