Respiratory gated shock delivery by subcutaneous-implantable medical device

An implantable medical system, comprising:

• a lead having subcutaneous first electrode, the first electrode configured to be positioned along an anterior of a chest and extend along a side of a sternum;
• a subcutaneous implantable medical device (S-IMD) configured to be positioned along a lateral region of a rib cage, the S-IMD comprising memory and one or more processors, the memory to store program instructions;
• and the one or more processors that, when executing the program instructions, are configured to:
• declare at least one of a ventricular fibrillation or ventricular tachycardia arrhythmia based on sensed cardiac events;
• obtain a respiration proxy signal indicative of respiration, the respiration proxy signal varying over a respiration cycle;
• track a respiration state related (RSR) characteristic from the respiration proxy signal related to peak expiration;
• gate delivery of a ventricular defibrillation shock based on occurrence of a respiration-gated (RG) trigger in connection with the RSR characteristic, the RG trigger corresponding to a point in time when the RSR characteristic indicates a select state within the respiration cycle;
• and
• deliver the ventricular defibrillation shock along shocking vector between the ¬S-IMD and the first electrode based on the RG trigger to time delivering of the ventricular defibrillation shock to occur during the select state within the respiration cycle, the ventricular defibrillation shock having an amount of energy to treat the at least one of the ventricular fibrillation or ventricular tachycardia arrhythmia, the select state related to the peak expiration of the respiration cycle.