Statistical validation of new ventricular tachycardia detection schemes.

The reliability of three new template matching techniques for detecting ventricular tachycardia (VT) using intracardiac waveform morphology was assessed using nonparametric tolerance intervals. These new techniques, the bin area method (BAM) , the normalized area of difference (NAD), and the derivative area method (DAM), were compared with correlation waveform analysis (CWA), an established method of waveform analysis. All four methods are independent of amplitude fluctuations and produced a bounded similarity measure, H, between 1 and 1. Like CWA, BAM and DAM are independent baseline changes. The BAM adds five consecutive sample points to form bins, removes the mean value, and compares each waveform with a similarly processed template. The NAD is identical to BAM, except that the mean is not subtracted. The DAM uses the zero-crossings of the derivative of the template to partition the template into areas. The same partitioning is then enforced on each subsequent waveform, and partitioned areas are compared to the corresponding areas in the template. The BAM and DAM required only