Cardiac activation sequence monitoring and tracking

A method, comprising:

• sensing, at least in part implantably, a plurality of composite cardiac signals using a plurality of electrodes;
• performing an initial source separation using one or more of the detected plurality of composite signals, the initial source separation producing vectors;
• selecting one or more vectors from the plurality of vectors, the one or more selected vectors representative of depolarization of an area of the heart;
• sensing additional composite cardiac signals;
• performing a plurality of subsequent source separations using the additional composite cardiac signals;
• monitoring for a change in the selected one or more vectors between the initial source separation and the subsequent source separations;
• and
• detecting anomalous cardiac activity based on the change in the selected one or more vectors.

A cardiac system, comprising:

• a plurality of implantable electrodes configured for sensing a composite signal, thereby providing a plurality of composite signals;
• a housing configured for implantation in a patient;
• a controller provided in the housing;
• a signal processor;
• and
• a memory coupled to the signal processor;
• wherein the signal processor is configured to perform an initial source separation using one or more of the plurality of composite signals, the source separation producing one or more cardiac signal vectors associated with a cardiac depolarization sequence of an area of a heart, store vector information in the memory based on the initial source separation, perform a plurality of subsequent source separations using at least some of the plurality of composite signals that are sensed subsequent to the sensing of the one or more of the plurality of composite signals, monitor for a change in the one or more vectors between the initial source separation and the subsequent source separations using the stored vector information, and to produce an output based on the change in the one or more vectors.

An implantable cardiac device, comprising:

• means for sensing, at least in-part implantably, a plurality of composite signals over time using a plurality of cardiac electrodes;
• means for performing at least one initial source separation using one or more of the plurality of composite signals, the source separation producing one or more cardiac signal vectors associated with cardiac depolarization of an area of a heart;
• means for establishing a vector baseline based on the at least one initial source separation;
• means for performing at least one subsequent source separation using at least one of the plurality of composite signals;
• means for monitoring for a change in the one or more cardiac signal vectors relative to the vector baseline based on the at least one subsequent source separation;
• and
• means for detecting a cardiac condition based on the change in the one or more cardiac signal vectors.

A cardiac method, comprising:

• sensing a plurality of composite cardiac signals over time at a plurality of patient-internal locations;
• performing, patient-internally, an initial source separation using one or more of the sensed plurality of composite signals;
• producing, patient-internally, a cardiac signal vector associated with a cardiac depolarization sequence of an area of the heart based on the initial source separation;
• performing at least one subsequent source separation using at least one of the sensed plurality of composite signals;
• and
• detecting a change in the cardiac signal vector between the initial source separation and the at least one subsequent source separation, wherein sensing, performing the initial source separation, producing, performing the at least one subsequent source separation, and detecting are each performed at least in part by circuitry of a medical system.

A cardiac system, comprising:

• a plurality of implantable electrodes configured for sensing composite signals over time, thereby providing a plurality of composite signals;
• a housing configured for implantation in a patient;
• a controller provided in the housing and coupled to the plurality of implantable electrodes;
• and
• a memory provided in the housing and coupled to the controller;
• wherein the controller is configured to perform an initial source separation using one or more of the sensed plurality of composite signals, the source separation producing a cardiac signal vector associated with a cardiac depolarization sequence of an area of the heart, perform one or more subsequent source separations using at least one of the plurality of composite signals, and detect a change in the cardiac signal vector indicative of cardiac arrhythmia between the initial source separation and the at least one subsequent source separation.