Patent ID: 7933650

Claim:
A cardiac rhythm management (CRM) system, comprising: a sensing circuit to sense one or more cardiac signals; a cycle length detector, coupled to the sensing circuit, to detect cardiac cycle lengths from the one or more cardiac signals, the cardiac cycle lengths each being a time interval between two consecutively detected heart beats; a tachyarrhythmia detector, coupled to the cycle length detector, to detect a tachyarrhythmia episode using the cardiac cycle lengths; a tachyarrhythmia classifier, coupled to the tachyarrhythmia detector, to classify the detected tachyarrhythmia episode; a pacing output circuit to deliver pacing pulses; and an anti-tachyarrhythmia pacing (ATP) selection module, coupled to the sensing circuit and the tachyarrhythmia classifier, to select a therapy mode based on the classification of the detected tachyarrhythmia episode and morphology of one of the one or more cardiac signals, the ATP selection module including: a morphological parameter generator including an ATP index calculator including a QRS width detector configured to detect QRS widths from the one of the one or more cardiac signals and a ratio calculator configured to calculate an ATP index as a ratio of the QRS width of a heart beat to the cardiac cycle length associated with the heart beat; a mean index calculator configured to calculate a mean ATP index of the ATP indexes calculated for a plurality of heart beats; and a standard deviation calculator configured to calculate a standard deviation of the ATP indexes calculated for the plurality of heart beats; and an ATP selector configured to select an ATP therapy from a plurality of therapies in response to the mean ATP index and the standard deviation indicating a likeliness of success of the ATP therapy.