Arrhythmogenic right ventricular dysplasia

Background

• Second most common cause of sudden cardiac death in young patients
  • Up to 20% of sudden cardiac deaths in young people
• Usually occurs in people of Greek or Italian descent
• Male:Female = 3:1
• 1:1000-10,000 in the US
• Fibro-fatty replacement of right ventricular myocardium
• Two forms:
  • Autosomal dominant
    • Variable penetrance
  • Autosomal recessive
    • Naxos disease (Palmoplantar keratoderma)

Clinical Features

• Palpitations (27%)
• Syncope (26%)
• Ventricular dysrhythmia/cardiac arrest (23%)
  • Especially occurring during exercise
• Family history of unexplained syncope or sudden death
• Dysrhythmias refractory to anti-dysrhythmic meds
• Asymptomatic (40%)
  • Usually these patients are identified through genetic testing of an affected or symptomatic family member
• Right ventricular failure (6%)
• Dilated cardiomyopathy
• Dyspnea
• Atypical chest pain (6%)

Differential Diagnosis

Cardiomyopathy

• Dilated cardiomyopathy
• Hypertrophic cardiomyopathy
• Restrictive cardiomyopathy
• Peripartum cardiomyopathy
• Takotsubo cardiomyopathy
• Arrhythmogenic right ventricular dysplasia

Syncope Causes

• Cardiovascular-mediated syncope
  • Dysrhythmias:
    • WPW (pre-excitation)
    • Long QT Syndrome/QT prolongation
    • Brugada Syndrome
    • Catecholaminergic polymorphic ventricular tachycardia
    • 2nd/3rd AV Block
    • Afib/aflutter
    • Vtach/torsades
    • Sick sinus syndrome
    • Arrhythmogenic right ventricular dysplasia
    • Short QT syndrome
  • Cardiovascular disease
    • Valvular Disease (AS, MS, tricuspid stenosis)
    • Aortic Dissection
    • Myocardial Infarction
    • CHF
    • Hypertrophic Cardiomyopathy
    • PE
    • Pericardial Tamponade
    • Myxoma
    • Pulmonary Hypertension
    • Pacemaker malfunction
• Neurally mediated syncope
  • Vasovagal:
    • Fear, pain, emotion, valsalva, breath-holding spell
  • Situational (associated with):
    • Coughing, micturition, defecation, vomiting, swallowing, postexercise
    • Carotid sinus stimulation
• Orthostatic hypotension-mediated syncope:
  • Volume depletion:
    • Dehydration (vomiting, diarrhea)
    • Hemorrhage, (Ectopic Pregnancy, Upper GI Bleed/Lower GI Bleeding, Abdominal Aortic Aneurysm)
    • Sepsis
  • Autonomic Dysreflexia
  • Autonomic failure due to meds
• Other serious causes
  • Stroke
  • SAH
  • TIA
  • Vertebrobasilar Insufficiency
  • Subclavian steal
  • Heat syncope
  • Hypoglycemia
  • Hyperventilation
  • Asphyxiation
  • Seizure
  • Narcolepsy
  • Psychogenic (anxiety, conversion disorder, somatic symptom disorder)
  • Toxic (drugs, carbon monoxide, etc.)

T Wave Inversions

• Normal in pediatrics
• Myocardial infarct (NSTEMI)
• Myocardial ischemia (Wellen's) - T waves go up, then down
• Hypokalemia - T waves go down, then up (or camel humped, one upright TW and upright U-wave in severe hypokalemia)
• Hyperkalemia
• Pulmonary embolism (RV strain)
• Pulmonary hypertension, acute or chronic
• Pulmonary disease - hyperventilation, pneumothorax, pneumonia
• LVH with strain pattern
• RVH
• Bundle branch block (both left and right)
• WPW
• Pericarditis (stage 3)
• CNS T waves (diffuse, deep)
• Arrhythmogenic right ventricular dysplasia (may also have epsilon wave)
• HOCM
• Paced rhythm
• Elevated intracranial pressure

Evaluation

ECG

• Epsilon wave
  • Seen in 30-50% of cases
  • Most specific finding
  • Small positive deflection at the end of the QRS complex
• V1-V3 T wave inversions
  • Seen in 85% of cases
  • Especially in patients >14 yrs old)
• Localised QRS widening
  • 110 ms in V1-V3
• Sudden VT episodes with LBBB morphology
• Prolonged S-wave upstroke
  • 55 ms in V1-3
  • Seen in 95% of cases

Imaging

Major and minor criteria rely on echo and cardiac MRI

• Echo
  • Hypokinetic and dilated right ventricle
  • Dilation of RVOT
• Cardiac MRI
  • Fibro-fatty infiltration
  • Thinning of right ventricular myocardium
  • RV aneurysm
  • RV dilatation
  • Regional wall motion abnormalities
  • Global systolic dysfunction
• Histological studies provide post-mortem diagnosis
  • May prompt testing in family members

Management

• Sotalol is the preferred anti-dysrhythmic
• Manage heart failure in the usual manner

Disposition

• Admission under cardiology if symptomatic
• Admission under cardiology if high-risk features:
  • Syncope due to cardiac arrest
  • Recurrent dysrhythmias not suppressed by drug therapy
  • Cardiac arrest in first-degree relative
• Incidental finding: Cardiology follow-up for further risk assessment and possible ICD placement or ablation

References

• Anderson EL. Arrhythmogenic right ventricular dysplasia. Am Fam Physician. 2006 Apr 15;73(8):1391-8.
• Perez Diez D, Brugada J. Diagnosis and Management of Arrhythmogenic Right Ventricular Dysplasia. E-Journal of the ESC Council for Cardiology Practice, European Society of Cardiology 2008.