Underdetection of ventricular fibrillation in implantable defibrillators using recurrence quantification analysis

Increased amplitude variation has been associated with undersensing of ventricular fibrillation (VF), and may be theoretically related to dynamic VF characteristics. This study evaluates whether changes in frequency content may contribute to undersensing by implantable cardioverter defibrillators (ICD), and more specifically the utility of using recurrence quantification analysis (RQA) (a method derived from nonlinear dynamics and successfully used in a variety of physiological signal evaluation tasks) to identify characteristics which contribute to the undersensing. RQA can reveal subtle signal properties not easily demonstrated by power spectrum, since RQA, is not subject to stationarity nor linearity constraints.