Sudden Cardiac Death and ARVD

Framework for Sudden Cardiac Death in a Young Patient

Helpful to think about these patients in 2 broad categories: 1) Structural Heart Disease; and 2) No Structural Heart Disease.

  • Structural Heart Disease

o   Hypertrophic Cardiomyopathy

o   Dilated Cardiomyopathy

o   Other causes of Cardiomyopathy (such as infiltrative)

o   Valvular heart disease

o   Congenital Heart Disease (Tetralogy of Fallot, VSD, Eisenmenger’s, etc)

o   Scar-mediated structural abnormalities & arrhythmias

o   Ischemic heart disease secondary to nonatherogenic coronary artery disease (arteritis, dissection, congenital artery anomalies)

  • No Structural Heart Disease

o   Ischemic heart disease: CAD with MI
Coronary artery embolism
Coronary artery spasm

o   Channelopathies: Long QT, Short QT, Brugada

o   Familial sudden cardiac death

o   Pre-excitation syndrome

o   Idiopathic ventricular fibrillation

o   Myocarditis

o   Tamponade

o   Aortic Dissection

** Also, do not forget non-cardiac causes of sudden cardiac death (pulmonary embolism, intracranial hemorrhage, central airway obstruction, drug-induced)

 

What is Arrhythmogenic Right Ventricular Dysplasia (ARVD)?

  • Also known as Arrhythmogenic right ventricular cardiomyopathy (ARVC)
  • Prevalence

o   1/2000 to 1/5000 in the general adult population. It is an important cause of sudden cardiac death in young adults!

o   Although rarely diagnosed in the United States, it has accounted for ~11% of overall cases of SCD in young adults in certain parts of Europe.

o   Affects men more frequently than woman, with an approximate ratio of 3:1.

o   Familial background has been demonstrated in >50% of cases (make sure to perform genetic testing in all 1st degree relatives).

  • Pathophysiology

o   RV myocardial atrophy with fibrofatty replacement, leading to ventricular electric instability.

o    Now believed to be a genetic defect in desmosomes (flashback to Step1 studying), resulting from defective cell adhesion proteins such as plakoglobin, desmoplakin, plakophilin-2 (PKP2 gene), and desmoglein-2.

o    Mainly an autosomal dominant pattern of inheritance, although an autosomal recessive variant has been seen.

  • Clinical Manifestations:

o   Symptoms: palpitations (67%), syncope (32%), atypical chest pain (27%), dyspnea (11%), RV failure (6%)

o   Ventricular arrhythmias

o   Supraventricular tachyarrythmias: may be present in up to 25% of patients with ARVC.

o   In patients with autosomal recessive disease, there have been associations with palmoplantar keratosis and wooly hair!

  • EKG Findings:

o   QRS prolongation: due to delayed RV activation

o   Incomplete or complete RBBB: due to conduction delay in the terminal Purkinje system

o   Epsilon wave: due to low amplitude potentials caused by delayed activation of some portion of RV

o   Inversion of T waves in the right precordial leads

  • Diagnostic Criteria: Complicated diagnostic criteria is available for us to reference online via the 2010 revised Task Force Criteria
  • Treatment:

o   Activity restriction: there is an association between exercise and induction of VTs.

o   Beta blockers: No firm evidence on benefit of beta blockers

o   ICD: primary prevention for high risk patients or secondary prevention in those with prior sustained ventricular arrhythmia

o   Antiarrhythmic drugs: may reduce frequency of sustained and nonsustained ventricular arrhythmias, but have not been shown to reduce the risk of SCD.

o   Cardiac transplantation: rarely for patients who develop heart failure symptoms or ventricular arrhythmias that are progressive despite use of meds and ICD.

 

Evernote Link: https://www.evernote.com/shard/s338/sh/b3a47f88-0cca-44eb-bfe1-becd541368d9/1a348588ac22a942808d675ee0389a78

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