ExtraVascular Implantable Cardiac Defibrillator Continued Access Study

Inclusion Criteria: 1. Patient has a Class I or IIa indication for implantation of an ICD according to the ACC/AHA/HRS Guidelines.\[1\] 2. Patient is willing and able to sign and date the Informed Consent Form for their participation in the study. 3. Patient is at least 18 years of age and meets age requirements per local law. 4. Patient is geographically stable and willing and able to comply with the study procedures and visits for the duration of the follow-up. Exclusion Criteria: 1. Patient has indications for bradycardia pacing\[2\] or Cardiac Resynchronization Therapy (CRT)\[3\] (Class I, IIa, or IIb indication). 2. Patients with an existing pacemaker, ICD, or CRT device or leads. 3. Patients with these medical interventions are excluded from participation in the study: * Prior sternotomy * Any prior medical condition or procedure that leads to adhesions in the anterior mediastinal space (i.e., prior mediastinal instrumentation, mediastinitis) * Prior abdominal surgery in the epigastric region * Planned sternotomy * Prior chest radiotherapy Or any other prior/planned medical intervention not listed that precludes their participation in the opinion of the Investigator. 4. Patients with these medical conditions or anatomies are excluded from participation in the study: * Hiatal hernia that distorts mediastinal anatomy * Marked sternal abnormality (e.g., pectus excavatum that impedes the substernal tunneling path or procedure) * Decompensated heart failure * COPD with oxygen dependence * Gross hepatosplenomegaly Or any other known medical condition or anatomy type not listed that precludes their participation in the opinion of the Investigator. 5. Patients with a medical condition that precludes them from undergoing defibrillation testing: * Severe aortic stenosis * Current Intracardiac LA or LV thrombus * Severe proximal three-vessel or left main coronary artery disease without revascularization * Hemodynamic instability * Unstable angina * Recent stroke or transient ischemic attack (within the last 6 months) * Known inadequate external defibrillation * LVEF \< 20% * LVEDD \>70 mm Or any other known medical condition not listed that precludes their participation in the opinion of the Investigator. 6. Patient with any evidence of active infection or undergoing treatment for an infection. 7. Patient is contraindicated from temporary suspension of oral/systemic anticoagulation. 8. Patient with current implantation of neurostimulator or any other chronically implanted device that delivers current in the body. 9. Patient meets ACC/AHA/HRS or ESC clinical guideline Class III criteria for an ICD (e.g., life expectancy of less than 12 months). 10. Patient is enrolled or planning to enroll in a concurrent clinical study that may confound the results of this study, without documented pre-approval from a Medtronic study manager. 11. Patient with any exclusion criteria as required by local law (e.g., age or other). 12. Pregnant women or breastfeeding women, or women of childbearing potential and who are not on a reliable form of birth regulation method or abstinence\* (\*If required by local law, women of child-bearing potential must undergo a pregnancy test within seven days prior to EV ICD Continued Access Study procedures)