Template matching techniques for electrophysiologic signals: a practical, real-time system for detection of...

Time domain template matching morphology techniques have been proposed for inclusion in implantable cardioverter defibrillators (ICDs) for the detection of ventricular arrhythmias from intraventricular electrograms (IVEGs). However, ICDs have limited battery capacity which necessitate the use of low current drain algorithms. Although more computationally efficient template matching algorithms have been developed, none have incorporated the limitations inherent in current ICDs. An external ICD sensing prototype system was developed which filters, digitizes, and analyzes IVEGs during electrophysiology studies. Two template matching IVEG metrics, amplitude normalized area of difference and signature analysis, are calculated. These metrics are being tested clinically for their accuracy in differentiating ventricular tachycardia and sinus rhythm IVEGs.