A method and system for discrimination of supraventricular tachycardia and ventricular
tachycardia events. Morphological features points are extracted from normal sinus
rhythm (NSR) complexes and used to generate a NSR template. A numerical convolution
is performed using the NSR template and the feature points for each sensed NSR
to give a NSR filter output. Using a plurality of NSR complexes, a median NSR filter
output template is determined, where the median NSR filter output template has
a median value for each value in the NSR filter output. The median NSR filter output
template is then used during a tachycardia event to distinguish tachycardia events
as either ventricular tachycardia events or supraventricular tachycardia events.