Cardiac Sarcoidosis

Cardiac sarcoidosis is non caseating granulomatous infiltration of the myocardium, found in 25% of sarcoidosis patients at autopsy but clinically manifest in about 5%.

Isolated cardiac sarcoidosis occurs in a subset.

Granulomas and fibrosis affect basal septum (conduction), left ventricular free wall and papillary muscles.

Manifestations: AV block (can be the first presentation in patients under 60), ventricular tachycardia, sudden death, heart failure.

Prognosis depends on ejection fraction and arrhythmia burden.

• Palpitations, syncope, presyncope, dyspnoea, chest pain, sudden cardiac arrest.
• Young to middle aged adults with unexplained high grade AV block or VT.
• Extracardiac: pulmonary symptoms, hilar adenopathy, uveitis, erythema nodosum, lupus pernio, hypercalcaemia, arthropathy.

• ECG: conduction block, bundle branch block, fragmented QRS, ventricular ectopy.
• Echocardiography: basal septal thinning, regional wall motion abnormalities, reduced ejection fraction, aneurysm.
• Cardiac MRI: patchy, mid wall or epicardial late gadolinium enhancement.
• FDG PET (with dietary preparation of high fat low carbohydrate diet and fast) shows focal uptake (active inflammation) and perfusion defects.
• Whole body imaging (chest CT, PET) and biopsy of an accessible extracardiac lesion; endomyocardial biopsy has low yield (20 to 30%). Serum ACE, calcium, soluble IL 2 receptor.
• Exclude giant cell myocarditis, ARVC and Lyme carditis.
• Holter monitoring and electrophysiology study.

• Corticosteroids first line: prednisolone 30 to 40 mg daily for 4 to 12 weeks, then taper to 5 to 10 mg over 6 to 12 months; repeat PET to guide.
• Steroid sparing agents: methotrexate 10 to 20 mg weekly with folic acid, azathioprine 2 mg/kg, mycophenolate mofetil 1 to 1.5 g twice daily; infliximab 5 mg/kg or adalimumab 40 mg for refractory disease.
• Heart failure therapy (ACE inhibitor, beta blocker, MRA, SGLT2 inhibitor, diuretics).
• Device therapy: pacemaker for AV block; ICD for sustained VT, resuscitated arrest, ejection fraction 35% or less, or in those with preserved ejection fraction with late gadolinium enhancement and indications for pacing (ICD with pacing capability).
• Antiarrhythmics (amiodarone, sotalol) and catheter ablation for recurrent VT; immunosuppression reduces arrhythmia burden.
• Bone protection, Pneumocystis prophylaxis (co trimoxazole 960 mg three times weekly) with combination immunosuppression.
• Cardiac transplantation for refractory disease. Multidisciplinary care with pulmonology and cardiology.