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Studies have shown that at least 11-12% of patients with implantable cardioverter-defibrillators (ICDs) receive inappropriate shocks. The leading cause of inappropriate shocks is supraventricular tachycardia including atrial fibrillation and sinus tachycardia. Recent studies have shown that current algorithms based on electrogram morphology have poor positive predictive value. The current study evaluates whether activation timing can distinguish sinus rhythm from ventricular tachycardia.
A retrospective analysis on stored ICD intracardiac events was performed offline on 19 sinus rhythm (SR) and 14 ventricular tachycardia (VT) events from 17 patients using Matlab. A baseline sinus reference activation sequence was created from the first available sinus rhythm event for each patient. The signal was rectified without further filtering. Using the peak far-field signal as time 0, the activation difference (AD) between near- and far-field peak signals was measured and averaged for three ventricular beats. The same technique was then applied to SR complexes stored during later events as well as to VT events. The activation shift (AS) between each SR and VT event was measured by subtracting each AD for SR and VT from the corresponding baseline sinus reference activation difference. Because the data were not normally distributed, they are expressed using median (25th, 75th percentiles). Non-parametric statistical methods were used.
VT had a significantly larger activation shift compared to SR (23.3 (9.2, 32.9) msec vs. 1.7 (0.0, 1.7) msec, p < 0.0001). A receiver operating characteristic curve analysis of the ability of AS to distinguish SR from VT had an area under the curve of 0.9624 (95% CI: 0.8966-1.0000).
Analysis of activation timing from ICD intracardiac electrograms may be an alternative to electrogram morphology template matching to distinguish VT from supraventricular tachycardias.
Oral Contributions West, Room 3009
Saturday, March 09, 2013, 9:15 a.m.-9:30 a.m.
Session Title: Management Issues in the Pacemaker and ICD Patient
Abstract Category: 8. Arrhythmias: Devices
Presentation Number: 903-8
- 2013 American College of Cardiology Foundation