Up to 15 subjects will be enrolled to evaluate initial safety and performance of the AtaCor Temporary Pacing System. Safety will be evaluated through analysis of all Adverse Events. Performance will be evaluated through (1) the incidence of successful StealthTrac Lead placement using the MACH I Delivery Tool, (2) electrical performance measurements, such as pacing capture thresholds, sensed R-wave amplitudes, pacing impedance and skeletal muscle stimulation at rest. Appropriate sensing and pacing capture will be ascertained from ECG Holter Monitor recordings during periods of in-hospital ambulation.

Enrolled Subjects will have both a market-released transvenous pacing lead and investigational StealthTrac Temporary Pacing Lead placed and evaluated. During the placement procedure, diagnostic echocardiograms will be performed to detect any new pericardial effusions. Once inserted, the StealthTrac Lead will be used to deliver high rate pacing (160 to 220 BPM) in clinically appropriate Subjects, to demonstrate suitability for use in transcatheter procedures that require brief periods of temporary pacing. Lead positions will be documented using fluoroscopic images before the Subject leaves the procedure room. On the following two days after the procedure, electrical performance will be evaluated in multiple postures and appropriate pacing and sensing will be confirmed during activity using ECG Holter monitor recordings. Subjects will also be asked patient-centric questions about their experience with the StealthTrac Lead throughout the study period. Evaluations will continue for a minimum of two (2) and a maximum of seven (7) days after the index procedure. Prior to StealthTrac Lead removal, an X-Ray will be taken to document the final lead position and diagnostic echocardiography will be performed to (1) detect any latent pericardial effusions and (2) assess differences in cardiac function with intrinsic conduction and while pacing. A final follow-up will be performed 25-30 days after removal to identify any latent adverse events before the Subject exits the study.

Inclusion Criteria:

1. Indicated for closed-chest cardiac invasive procedure with the potential for intra-procedural or post-procedural bradycardia and willing to be hospitalized for a minimum of 2 days post procedure.

   Examples of such procedures include: transfemoral transcatheter aortic valve replacement (TAVR), balloon valvuloplasty, permanent pacemaker implantation and pacing lead extractions/revisions.

2. Physically and mentally capable of providing informed consent.

3. At least 18 years of age or of legal age to provide consent as required by local and national requirements.

Exclusion Criteria:

1. Contraindicated or clinically unsuitable for transvenous lead placement;
2. Implanted with an implantable cardioverter defibrillator (ICD) or transvenous defibrillation lead at the time of enrollment;
3. History of a prior sternotomy (median or partial);
4. History of prior surgery with disruption of the lung, pericardium or connective tissue between the sternum and pericardium;
5. History of significant anatomic derangement of the thorax (e.g., pectus excavatum), prior chest radiation therapy or other reasons which may cause pericardial adhesions or complicate the AtaCor Temporary Pacing System insertion procedure;
6. History of pericardial disease, pericarditis or mediastinitis;
7. History of chronic obstructive pulmonary disease (COPD);
8. NYHA functional classification IV at the time of enrollment;
9. History of congenital heart disease;
10. Patients with circumstances that prevent data collection or follow-up, including conditions that prevent ambulation and testing in multiple postures;
11. BMI ≥ 35 kg/m2;
12. History of allergies to any study device components;
13. Pregnant or lactating (current or anticipated during study follow up); and
14. Participation in any concurrent study without prior, written approval from the Sponsor.

30 Days