Effectiveness of the EMPOWER™ Modular Pacing System and EMBLEM™ Subcutaneous ICD to Communicate Antitachycardia Pacing

Inclusion Criteria: * Patient who meets Class I, IIa, or IIb guideline ICD indications\[i\],\[ii\], or who has an existing TV-ICD\[iii\] or S-ICD\[iv\] * Patient who is deemed to be at risk for MVT based on at least ONE of the following: * History of Non-Sustained MVT with LVEF ≤ 50% * History of sustained VT/VF (secondary prevention) with LVEF ≤ 50% or significant cardiac scar\* * History of syncope deemed to be arrhythmic in origin * History of ischemic cardiomyopathy with LVEF ≤35% * History of non-ischemic cardiomyopathy with LVEF ≤35% and significant scar\* * Patient who is willing and capable of providing informed consent (which is not to include the use of a legally authorized representative (LAR) for documentation of informed consent) and participating in all testing associated with this investigation at an approved study site and at the intervals defined by this protocol * Patient who is age 18 years or above, or of legal age to give informed consent specific to state and national law Exclusion Criteria: * Patient with an ongoing complication due to Cardiac Implantable Electronic Device (CIED) infection or CIED explant * Transvenous lead remnants within the heart from a previously implanted CIED (Note: transvenous lead remnants outside the heart (e.g., in the SVC) are allowed) * Patient with a known LA thrombus * Patient with a ventricular arrhythmia due to a reversible cause * Patient indicated for implantation of a dual chamber pacemaker or cardiac re…