Annotation of slow electrophysiological (EP) cardiac paths related to ventricular tachycardia (VT)

A system for evaluation of electrical propagation in a heart of a patient, the system comprising:

• a catheter having a plurality of electrodes configured to apply a pacing signal to the heart of the patient;
• one or more processors;
• and
• a non-transitory computer readable medium storing a plurality of instructions, which when executed, cause the one or more processors to:
• apply a pacing signal to the heart of the patient by the electrodes on the catheter, the pacing signal comprising (i) a sequence of normal pacing stimuli at sinus-rate intervals, and (ii) one or more abnormal pacing stimuli at abnormal intervals that are shorter than the sinus-rate intervals;
• receive from the catheter electrodes, in response to the applied pacing signal, a cardiac signal that is sensed by the catheter electrodes at a location in the heart;
• and
• identify and annotate a model response from evoked potentials in the cardiac signal caused by the normal pacing stimuli, the annotated model response being one of the evoked potentials having a high correlation based upon a prespecified metric to the other evoked potentials in the cardiac signal;
• determine, for each interval between paces of the paced signal, scorings of correlations with the model response along each of the respective intervals between paces of the paced signal;
• annotate a first set of the evoked potentials in the cardiac signal caused by the normal pacing stimuli and a second set of the evoked potentials in the cardiac signal caused by the one or more abnormal pacing stimuli, the first and second sets of evoked potentials being other than the evoked potential of the model and being annotated based upon the scorings of correlations, each annotation in each interval of the paced signal being identified as an index that received the highest scoring with the model response for that interval;
• determine a first time delay between the normal pacing stimuli and the resulting evoked potentials in the cardiac signal and a second time delay between the abnormal pacing stimuli and the resulting evoked potentials in the cardiac signal;
• determine a decremental time delay, the decremental time delay being a time difference between the first time delay and the second time delay;
• and
• cause an EP map of at least a portion of the heart to be presented on a graphical user interface (GUI) electronically coupled to the one or more processors, with a graphical indication of the decremental time delay presented at the one or more locations in the heart.