Tachyarrhythmia detection and discrimination based on curvature parameters

An implantable cardiac rhythm management device comprising:

• a ventricular channel input circuit to receive a sampled ventricular input signal for an epoch;
• an atrial channel input circuit to receive a sampled atrial input signal for the epoch;
• a controller coupled to the ventricular channel input circuit and coupled to the atrial channel input circuit, the controller adapted to determine relative timing between ventricular characteristic points and atrial characteristic points, each characteristic point determined based on a curvature series generated as a function of the input signals, each characteristic point having a time of a lobe in the curvature series;
• and
• a discriminator circuit coupled to the controller and adapted to classify the epoch based on a comparison of a first function of the atrial characteristic points and a second function of the ventricular characteristic points,
• wherein the controller is adapted to compute a ventricular curvature series using the sampled ventricular input signal for the epoch and an atrial curvature series using the sampled atrial input signals for the epoch, identify lobes using a curvature threshold value in each of the ventricular curvature series and the atrial curvature series, generate the ventricular characteristic points each associated with a lobe of the identified lobes in the ventricular curvature series, and generate the atrial characteristic points each associated with a lobe of the identified lobes in the atrial curvature series, wherein the ventricular curvature series includes curvatures each computed as a non-linear function of first and second derivatives of the sampled ventricular input signal, and the atrial curvature series includes curvatures each computed as a non-linear function of first and second derivatives of the sampled atrial input signal.