Discrimination of ventricular tachycardia from sinus tachycardia by antitachycardia devices: value of median filtering.
Rate and rate variation algorithms used by implantable devices designed for management of life-threatening arrhythmias have major limitations in separating physiologic sinus tachycardia (ST) from pathologic ventricular tachycardia (VT) requiring therapy. These algorithms presently utilize criteria such as simple heart rate, stability of rate, or derivative of rate (sudden onset) which assumes a gradual onset for ST and an abrupt onset for VT. An alternative method employing median filtering was designed, tested, and compared to a previously published sudden onset rate algorithm using the same data set for analysis of performance. In 50 patients, the onset of ST during exercise and onset of VT were analysed. To accommodate occasional outlying intervals which might affect rate derived by averaging, a five-cycle median filter was used to smooth heart rate. Results from using a 'fixed-interval' or a 'percent' change in the median gave better discrimination of ST and VT than previously published 'fixed-interval' or 'percent' change algorithms. The superiority of median filtering performance was validated by statistical measures.
Chiang
C M
CM
Department of Electrical Engineering and Computer Science, School of Engineering, University of Michigan, Ann Arbor.
Jenkins
J M
JM
DiCarlo
L A
LA
D000465:Algorithms; D003937:Diagnosis, Differential; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D010138:Pacemaker, Artificial; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013616:Tachycardia, Sinus / Q000175:diagnosis* / Q000628:therapy; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000628:therapy*