Arrhythmogenic right ventricular dysplasia

Background

In vitro MRI and corresponding cross section of the heart in ARVD show RV dilatation with anterior and posterior aneurysms (17-year-old asymptomatic male athlete who died suddenly during a soccer game).

• 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 dysrhythmias/cardiac arrest (23%)
  • Especially occurring during exercise
• Family history of unexplained syncope or sudden death
• Dysrhythmias refractory to antidysrhythmic 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 in Lead V1

• 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

MRI in a patient affected by ARVC/D (long axis view of the right ventricle): note the transmural diffuse bright signal in the RV free wall on spin echo T1 (a) due to massive myocardial atrophy with fatty replacement (b).

Major and minor criteria rely on echo and cardiac MRI

• Echocardiography
  • 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

• Beta blockers or amiodarone to suppress ventricular dysrhythmias
  • Sotalol is preferred
• ICD implantation if high-risk features
• Ablation of conduction pathways
• Treat heart failure with diuretics, ACE inhibitors
• Heart transplant

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.