RECOVER-AUTO; IVIG or Ivabradine for PASC

Inclusion Criteria: 1. ≥ 18 years of age at the time of enrollment 2. Previous suspected, probable, or confirmed SARS-CoV-2 infection, as defined by the Pan American Health Organization12ɸ ɸ Enrollment of participants with suspected or probable SARS-CoV-2 infection will only be allowed if they occurred before May 1, 2021 and be limited to no more than 10% of the total sample size per Study Drug Appendix. Refer to the Manual of Procedures (MOP) for details. Suspected case of SARS-CoV-2 infection - Three options, A through C: A. Meets the clinical OR epidemiological criteria. 1. Clinical criteria: Acute onset of fever AND cough (influenza-like illness) OR Acute onset of ANY THREE OR MORE of the following signs or symptoms: fever, cough, general, weakness/fatigue, headache, myalgia, sore throat, coryza, dyspnea, nausea, diarrhea, anorexia. 2. Epidemiological criteria: Contact of a probable or confirmed case or linked to a COVID-19 cluster; or B. Presents with acute respiratory infection with history of fever or measured fever of ≥ 38°C; and cough; with onset within the last 10 days; and who requires hospitalization); or C. Presents with no clinical signs or symptoms, NOR meeting epidemiologic criteria with a positive professional use or self-test SARS-CoV-2 antigen-Rapid Diagnostic Test. Probable case of SARS-CoV-2 infection, defined as meets clinical criteria above AND is a contact of a probable or confirmed case or is linked to a COVID-19 cluster. Confirmed case of SARS-CoV-2 infection - Two options, A through B: A. A person with a positive nucleic acid amplification test, regardless of clinical criteria OR epidemiological criteria; or B. Meeting clinical criteria AND/OR epidemiological criteria (See suspect case A). With a positive professional use or self-test SARS-CoV-2 Antigen-Rapid Diagnostic Test. 3. Moderate, self-identified autonomic symptoms (defined as COMPASS-31 \>25) following a SARS-CoV-2 infection that has persisted for at least 12 weeks and is still present at the time of consent 4. OHQ/OIQ, question 1 score \>2

Exclusion Criteria: 1. Known pregnancy, breast-feeding, or contemplating pregnancy during the study period 2. Known active acute SARS-CoV-2 infection ≤ 4 weeks from enrollment 3. Known renal failure (eGFR \<20ml/1.73 m²) 4. Known atrial fibrillation or significant cardiac arrhythmia 5. Known cardiovascular conditions such as heart failure (Class 3-4), severe valvular disease, symptomatic ischemic coronary artery disease, revascularization for PAD/CAD within the past 6 months 6. Clinically significant atherosclerotic disease, defined as history of stroke or myocardial infarction or revascularization 6 months prior to enrollment and/or current symptomatic angina 7. Existing uncontrolled hypertension 8. History of significant hypercoagulability disorders 9. Active or recent thrombosis