Moffitt AM Report 4/25/17: Complete Heart Block and Cardiac Sarcoid


Good morning everyone!

Thank you Carine and Tim for presenting the case of a middle aged man with a history of complete heart block (of unclear etiology) status post PM placement, who presented with evidence of L and R sided thromboembolism (PE and LV thrombus) as well as new cardiomyopathy, who was ultimately diagnosed with cardiac sarcoidosis!





  • New onset heart block in a young person cannot be assumed to be native conduction disease. We must rule out secondary causes (toxic/metabolic, infiltrative, or ischemic processes).
  • Malignancy is the most common cause of a hemorrhagic, pericardial effusion
  • Cardiac sarcoidosis is rare, and has been described in 5% of patients with systemic sarcoid, but autopsy studies indicate that subclinical cardiac involvement is present in up to 70% of cases


Complete Heart Block in a Young Patient

  • In >50% of cases, no specific, reversible causes are identified. However, when a young patient presents with CHB, the diagnosis idiopathic progressive conduction disease should NOT be assumed (always search for secondary, reversible causes).
  • Congenital Causes of Complete Heart Block
    • Autoimmune congenital CHB: usually due to transplacental passage of maternal autoantibodies to Ro/SSA and/or La/SSB that damage developing conduction tissue
    • Structural heart abnormalities due to congenital heart disease (eg congenitally corrected transposition of great arteries, endocardial cushion defects)
    • Idiopathic familial congenital CHB
  • Acquired Causes of Complete Heart Block
    • Iatrogenic: meds, post-cardiac surgery, post-catheter ablation, post-TAVR
    • Pathologic : Ischemia : Infiltrative – sarcoidosis, amyloidosis, malignancies : Myocarditis (eg Lyme Disease) : Endocarditis with abscess formation : Electrolyte abnormalities : Endocrinopathy

Cardiac Sarcoidosis (Blast from the past of VA & Moffitt Pearls!)

  • Clinical evidence of myocardial involvement have been described in 5% of patients with systemic sarcoid, but autopsy studies indicate that subclinical cardiac involvement is present in up to 70% of cases!
  • Clinical Manifestations depend on location and extent of granulomatous inflammation.
    • AV block or bundle-branch block: most common finding in patients with clinically evident cardiac sarcoid
    • Tachyarrhythmias
    • Cardiomyopathy
    • CHF
    • Sudden cardiac death
    • Pericardial disease
  • When to suspect cardiac sarcoidosis?
    • Young adults (< 55 yoa) with unexplained 2nd or 3rd degree AV block
    • Young adults (< 55 yoa) with new ECG abnormalities or symptoms in the absence of coronary artery disease or inherited CV disease
    • Patients with sustained monomorphic VT
    • Patients with clinical diagnosis of extracardiac sarcoidosis
  • Diagnosis: Challenging and frequently missed/delayed
    • There are various guidelines proposed by various different societies! Usually based on a combination of ECG, echo, MRI/PET, and endomyocardial biopsy
    • ECHO: 1st line imaging. LV dilatation, septal thinning, segmental or global hypokinesia of the LV or RV, aneurism formation, valvular regurgitation, simulated LV hypertrophy from infiltration into the myocardium.
    • Cardiac MRI: Technique of choice for the dx of cardiac sarcoid w/ the highest sensitivity and specificity. Late gadolinium enhancement (LGE) may have prognostic value in evaluating chronic sarcoid as you have scar formation and increased risk of death presumably from arrhythmia.
    • Cardiac PET: Excellent imaging modality for active sarcoid, but less specific as can have false positives with other inflammatory myocardial diseases.


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