Wavelet-based tachycardia discrimination in ICDs: Impact of posture and electrogram configuration

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Inappropriate therapy delivery is a significant concern in implantable cardioverter defibrillator (ICD) management.
• A novel morphology-based algorithm (wavelet feature) aids in differentiating ventricular and supraventricular tachycardia.
• The study investigates the performance of this wavelet algorithm across various electrogram (EGM) configurations and body positions.

Purpose of the Study:

• To evaluate the performance of the wavelet algorithm in differentiating tachyarrhythmias.
• To assess the impact of different electrogram (EGM) configurations on wavelet algorithm accuracy.
• To determine the influence of body position changes on EGM morphology and algorithm performance.

Main Methods:

• Twenty-eight patients with single-chamber Medtronic ICDs were included.
• Electrogram (EGM) templates were acquired in a supine position using various configurations: RV coil-can, RV coil-SVC coil, tip-ring, and SVC coil-can.
• Morphologic similarity (match percentage) was compared between supine templates and EGMs recorded in different body positions (supine, lateral, sitting, standing, walking).

Main Results:

• A total of 9,775 intracardiac EGMs were analyzed.
• Median match percentages varied by configuration: RV coil-can (88%), RV coil-SVC coil (88%), tip-ring (82%), and SVC coil-can (73%).
• Correct classification rates (>=70% match) were significantly higher for RV coil-can (95%), RV coil-SVC coil (91%), and tip-ring (91%) compared to SVC coil-can (58%).

Conclusions:

• Wavelet-based morphology scores in ICDs are sensitive to body position changes.
• The RV coil-can, RV coil-SVC coil, and tip-ring configurations demonstrate relatively minor variations in morphology scores.
• The SVC coil-can configuration exhibits considerable score variability and should be avoided when utilizing the wavelet algorithm.