Active implantable medical defibrillation device

An active implantable medical device comprising:

• a detection electrode;
• and
• a pulse generator configured to deliver at least one of a defibrillation shock or antitachycardia pacing stimulation pulses to at least one ventricle of a patient carrying the device, the pulse generator comprising a memory having instructions stored thereon and a processor configured to execute the instructions to cause the pulse generator to:
• collect at least two different endocardial electrogram (EGM) signals during a cardiac cycle and derive, from the EGM signals, at least two respective and distinct time components;
• combine the at least two time components into a parametric 2D characteristic curve representative of the cardiac cycle;
• derive, from the 2D characteristic curve, a geometrical descriptor representative of the 2D characteristic curve;
• determine a variation of the geometrical descriptor over the cardiac cycle;
• compare the variation of the geometrical descriptor with a predetermined threshold;
• and
• at each cycle of a detected tachyarrhythmia episode and when the variation of the geometrical descriptor is less than or equal to the predetermined threshold:
• measure and store values of a cycle-to-cycle variation in an amplitude of the at least one of the EGM signals;
• distribute the amplitude variation values into a plurality of classes, each class corresponding to an amplitude interval;
• and
• analyze a size of each of the plurality of classes to deliver at least one of an indicator of suspicion of an artifact of extracardiac origin or an indicator of a type of tachyarrhythmia selectively as a function of at least one predetermined criterion applied to the distribution of the amplitude variation values.