Prospective randomized controlled trial comparing low dose Prednisone(or Prednisolone)/Methotrexate combination to standard dose Prednisone(or Prednisolone) in patients diagnosed with acute active clinically manifest cardiac sarcoidosis and not yet treated.

The Investigators hypothesize that low dose Prednisone(or Prednisolone)/Methotrexate combination will be as effective as standard dose Prednisone(or Prednisolone), and result in significantly better quality of life and less toxicity than standard dose Prednisone(or Prednisolone).

Subjects meeting the study inclusion/exclusion criteria will be randomized equally to receive either:

Everywhere but Japan:

1. Prednisone 0.5 mg kg/day for 6-months (MAX dose 30 mg per day) or
2. Methotrexate 15-20 mg po, sc, or IM once a week for 6-months + Folic Acid OD (exact dose and directions at physician) for 6 months + Prednisone 20 mg day for 1 month, then 10 mg OD for 1 month, then 5 mg OD for one month then STOP

In Japan:

1. Prednisone or prednisolone 0.5 mg/kg po (max 30mg) for one month then reduce by 5 mg per month for five months or
2. Methotrexate 5-20mg po, sc or IM once week for 6-months +Folic Acid 2-5 mg OD for 6-months+Prednisone or prednisolone 20mg OD for 1 month then 10mg OD for 1 month then 5 mg OD one month

Methotrexate will be initiated at a dose of 15 mg once a week and increased to 20 mg once a week after 4 weeks if tolerated. In case of Methotrexate-induced side-effects general guidelines will be provided, however specific management will be left to the treating physicians. Folic acid will be taken to help reduce methotrexate side-effects.

Prior to randomization and study treatment all subjects will have the following baseline tests done: baseline safety blood work; FDG-PET scan with myocardial perfusion imaging; ECG; echo; and an optional bone mineral density scan. Cardiac MRI (CMR) is optional but strongly encouraged. Blood will be obtained for biomarker core-lab analysis. Biomarkers to be assayed will include highly sensitive Troponin I. Samples will be stored for future novel biomarker discovery. Quality of LIfe (QOL) questionnaires (KSQ, SAT and SF-36) will be completed prior to treatment start.

After therapy initiation subjects will be seen at 4 weeks, 8 weeks (methotrexate arm only), and 12 weeks, with a final visit at 6 months. Safety bloodwork and assessment for medication side effects, using a medication side-effect questionnaire, will be completed at all visits. At 12 weeks QOL questionnaires will be completed. The primary endpoint will be assessed at 6-months, when FDG-PET with myocardial perfusion imaging, ECG, echo, optional bone mineral density scan, QOL questionnaires, blood for biomarkers and device interrogation will be done. CMR may be repeated. Skin, muscle strength testing and neuropsychiatric assessment will be completed at 6 months as part of the composite glucocorticoid toxicity index.

After the 6 month visit. further management will be at the treating physician's discretion. Details of the physicians planned treatment following the 6-month PET scan will be collected.

Standardized protocols for all aspects of FDG-PET scans (i.e. patient preparation, image acquisition, image processing, transfer to the core lab and analysis at core lab) will be followed.

Inclusion Criteria:

(i) Cardiac sarcoidosis presenting with one or more of the following clinical findings:

• advanced conduction system disease (defined as Mobitz II AV block or third degree AV block)
• significant sinus node dysfunction (defined as average HR less than 40bpm when awake and/or sustained atrial arrhythmias)
• non- sustained or sustained ventricular arrhythmia
• left ventricular dysfunction (LVEF < 50%)
• right ventricular dysfunction (RVEF < 40%)

AND

(ii) No alternative explanation for clinical features

AND

(iii) Nuclear Imaging within six-months of enrollment consisting of FDG-PET scan with FDG uptake suggestive of active CS and myocardial perfusion imaging

AND ONE OR BOTH OF FOLLOWING

(iv) Positive biopsy for Sarcoid (either EMB or extra-cardiac)

(v) CT Chest showing features consistent with pulmonary sarcoidosis and/or mediastinal and/or hilar lymphadenopathy

Exclusion Criteria:

1. Current or recent (within two months) non-topical treatment for sarcoidosis
2. Current Oral/IV treatment of duration greater than 5 days
3. Currently taking Methotrexate or Prednisone for another health condition
4. Intolerance or contra-indication to Methotrexate or Prednisone
5. Patient does not meet all of the above listed inclusion criteria
6. Patient is unable or unwilling to provide informed consent
7. Patient is included in another randomized clinical trial
8. Patient has a contraindication to PET imaging or is unlikely to tolerate due to severe claustrophobia
9. Pregnancy (all women of child bearing age and potential will have a negative BHCG test before enrollment)
10. Breastfeeding
11. Women of childbearing age who refuse to use a highly effective and medically acceptable form of contraception throughout the study
12. Patients for whom the investigator believes that the trial is not in the interest of the patient