High Grade AV Block and Sarcoidosis

Happy election day, everyone!

Thank you Joe and Max for presenting a case of a middle-aged woman subacute history of exertional chest pain, presenting with syncope and high-grade AV block, found on evaluation to have clean coronary arteries. Differential included infiltrative processes (including cardiac sarcoidosis) versus Takotsubo cardiomyopathy!

TOP PEARLS

  • Frame cardiogenic syncope into: 1) Structurally normal heart vs 2) structurally abnormal heart. 1) Structural normal heart: arrhthymias (channelopathies), massive PE 2) Structurally abnormal heart: Valvulopathies, HOCM, infiltrative diseases, ischemia, tamponade

 

  • Takotsubo cardiomyopathy is a diagnosis of exclusion! As it closely mimics a myocardial infarction, ACS needs to be ruled-out first (other differentials include cocaine-related ACS, myocarditis, pheochromocytoma)
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Cardiac Sarcoidosis  

  • 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

Takotsubo Cardiomyopathy

  • Also known as: stress cardiomyopathy, apical ballooning syndrome, broken heart syndrome, etc.
  • Characterized by transient regional systolic dysfunction of the LV, mimicking an MI, but in the ABSENCE of angiographic evidence of obstructive CAD or plaque rupture.
  • Epidemiology : First described in 1990 in Japan! : 1-2% of patients presenting with troponin-positive ACS or suspected ST-elevation MI : Predisposition for post-menopausal women
  • Pathogenesis – Catecholamine hypothesis: stress causes catecholamine-induced microvascular spasm, and multi-vessel coronary artery spasm, resulting in myocardial stunning/toxicity
  • EKG findings: 1) ST elevation is a common finding! 43.7% of patients in the International Takotsubo Registry study had ST-elevations most commonly in anterior precordial leads 2) ST depression: Less common (7.7%) 3) Other less common findings: QT prolongation, T wave inversion, non-specific changes
  • Can Takotsubo cardiomyopathy present with high-grade heart block? Several case reports have been published about patients presenting with high-degree AV blocks in the setting of Takotsubo!
  • Cardiac biomarkers: elevated in MOST patients
  • Echo findings: Most common type is hypokinesis of apical segments, resulting in the systolic apical ballooning of the LV : Atypical variants: ventricular hypokinesis, basal hypokinesis, anterolateral segment hypokinesis

    Evernote Link: https://www.evernote.com/shard/s338/sh/de76c14e-be1a-4d27-8dd7-a093a9630a57/0cb7b94623e84aa8ea78640a2a353679

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