Subcostal Temporary Extravascular Pacing IV (STEP IV) Study

Inclusion Criteria: 1. At least 18 years old 2. Indicated for closed-chest cardiac invasive procedure (e.g., transcatheter valve replacement, balloon valvuloplasty, permanent pacemaker implantation and pacing lead extractions/revisions) Exclusion Criteria: 1. BMI ≥ 35 kg/m2 2. Septic shock 3. Severe anemia 4. Acute coronary syndrome within past 90 days 5. NYHA IV Functional Classification of heart failure within past 90 days 6. Circumstances that prevent data collection or follow-up (e.g., inability to perform a short walk with the Holter monitor) 7. Participation in any concurrent clinical study without prior written approval from the Sponsor 8. Inability or unwillingness to provide informed consent to participate in the Study Known prior history for any of the following: 9. Median or partial sternotomy 10. Surgery with disruption of the lung, pericardium or connective tissue between the sternum and pericardium 11. Significant anatomic derangement of or within the thorax (e.g., pectus excavatum, significant scoliosis) 12. Thoracic radiation therapy, pneumothorax, pneumomediastinum or other medical treatments/conditions which may complicate the AtaCor EV Temporary Pacing Lead System insertion procedure 13. Pericardial disease, pericarditis and mediastinitis 14. Medical treatments, surgeries or conditions that increase the potential for pericardial adhesions 15. FEV1 \< 1 liter 16. Surgically corrected congenital heart disease (not including catheter-based procedures) 17. Allergies to the device materials such as stainless steel, titanium, platinum, iridium, polyethylene, polyurethane, polycarbonate, and silicone