Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

By Baruch Berzon MD and Richard Sinert MD

Case Presentation

A 32 year-old male presents in August to EMS with complaints of “flutter in my chest” and light-headedness for an hour. The paramedics find a young man in mild distress who is Diaphoretic with a heart rate of 220 and a blood pressure of 110/69. The 3-lead ECG shows a wide-complex tachycardia at a rate of 220 BPM. They obtain IV access and preform a 12 –lead. They transmit the 12-lead and call you for consultation:

(From the European Society of Cardiology)

Clinical questions

Interpret the 12 lead?
Should they attempt to treat this chemically or electrically? If chemically, what is the drug of choice?
They converted the patient and get the following repeat ECG:

Now the patient is in your ED, his vital signs are normal. In addition to routine lab testing and cardiologic consultation for Ventricular Tacycardia, what else would you do for the care of this patient?

Overview with learning points

Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy or ARVD/C is one of the most arrhythmogenic forms of inherited cardiomyopathy and a cause of sudden cardiac death (SCD) in the young.¹ ARVD is the most common cause of sudden cardiac death in young athletes after Hypertrophic Cardiac Myopathy. ⁴

Pathophysiology-

ARVD/C is inherited in an Autosomal Dominant manner but because it has incomplete penetrance and variable expressivity, affected individuals have varying clinical courses. The 8 genes involved encode the Desmosome proteins that act as a structural connection between cardiac cells and are also involved in calcium hemostasis and cell-to-cell signaling. When cell-to-cell binding is affected, cells undergo apoptosis and are replaced by fat cells and fibrous tissue. The disease is characterized by fibro-fatty replacement of predominantly the right ventricle (RV), which predisposes patients to life-threatening ventricular arrhythmias as well as progressive mechanical ventricular dysfunction. As the infiltration progresses, it eventually can lead to LV involvement and failure as well. The fatty or fibrofatty infiltration occurs at the epicardium of the RV and often involves the “triangle of dysplasia” which is bordered by the apex, infundibulum and the inferior aspect of the RV (see image in above hyperlink) but can progress to include the myocardium as well as infiltration of the septum and LV.

Prevalence

ARVD/C has an estimated prevalence of 1 in 1000 to 1 in 5000 Caucasian individuals, although some studies report that the real prevalence could be higher due to under-recognition.²In some populations, it may be even more prevalent (Finish Study finds 1 in 200).³

Clinical presentation

ARVD/C usually presents in 3rd to fifth decade of life and patients experience syncope or Ventricular dysrhythmias ranging from PVC’s to VT to VF, Heart failure or sudden cardiac death.

Diagnosis

The diagnosis is complex for several reasons; the heterogeneity of presentation, the low yield of the endomyocardial biopsy (EMB), and the different genetics involved. The diagnosis is therefore based on Task Force criteria in six different aspects of the disease. They were initially published in 1994 and revised and validated in 2010. These are best summarized below⁵;

(Journal of Cariology)

The classic ECG finding is an Epsilon wave which is a low amplitude signal at the end of the QRS in V1-V3.

One can infer from the above that the testing required to make a definite diagnosis are not readily available in the ED. However a history of SCD in the family, previous unexplained syncopal episodes and an ECG with characteristic findings should raise the clinical suspicion for ARVD/C and prompt further testing.

Management

Initial management would always include the A, B, C’s. In unstable patients with ventricular arrhythmias, electric cardioversion is recommended. In stable patients, Amiodarone remains the most effective empirical antiarrhythmic drug for ventricular dysrhythmias.⁵ Checking electrolytes and looking for other precipitating factors such as infection behooves the Emergency clinician. Consultation with the Cardiologist is paramount to further investigate the possibility for ARVD. If suspected, the patient will undergo 2D echo and /or cardiac MRI, Signal average ECG, Holter monitoring, genetic analysis and invasive studies such as RV Angio and Biopsy (EMB). Counseling other members of the family for early diagnosis and prevention of the disease is recommended and relatives are further risk stratified based on history and further testing.⁵

Long term treatment includes antiarrhythmic drugs for prevention of arrhythmias and implantation of an AICD. Catheter ablation with new 3D mapping has heterogeneous results with success ranging from 45-85%. In patients with extensive heart failure or drug-refractory VT’s, heart transplantation is the last resort but this occurs very rarely.

In summary…

ARVD/C is a heterogenic disease that presents in young patients with syncope, VT’s or sudden cardiac death. The epsilon wave might be the first clue for the emergency physician to the possibility of ARVD/C and should prompt a through history, exam and appropriate diagnostic testing.

Extra! Extra! Read all about it–

Did you know that some ARVD/C had involvement of predominantly the LV? It should be called ALVD/C 🙂 ?

Did you know that sometimes ARVD/C is recessive and involves a cutaneous phenotype? (eg. Naxos disease or Carvajal syndrome)

That there is a known link between ARVD/C and myocarditis that is still waiting for YOU to clearly define?

FOAMED and REFERENCES:

http://www.escardio.org/Guidelines-&-Education/Journals-and-publications/ESC-journals-family/E-journal-of-Cardiology-Practice/Volume-7/Diagnosis-and-management-of-arrhythmogenic-right-ventricular-dysplasia

http://journal.frontiersin.org/article/10.3389/fphys.2012.00023/full comparison to RVOT

http://www.heartpearls.com/tag/epsilon-wave

http://lifeinthefastlane.com/ecg-library/basics/epsilon-wave/

http://www.hopkinsmedicine.org/heart_vascular_institute/clinical_services/centers_excellence/arvd/symptoms_diagnosis/genetics.html

http://www.af-ablation.org/?page_id=2034

http://www.revespcardiol.org/en/arrhythmia-and-right-heart-disease/articulo/13154581/ RVOT and Brugada looks at as well

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: Clinical challenges in a changing disease spectrum. te Riele A. et al; Trends in Cardiovascular Medicine, Volume 25, Issue 3, April 2015, Pages 191–198

Cardiovascular causes of sudden death in young individuals including athletes. Basso C. et al; Cardiology Review, 7 (1999), pp. 127–135

Population-prevalent desmosomal mutations predisposing to arrhythmogenic right ventricular cardiomyopathy. Lahtinen AM et al; Heart Rhythm.2011 Aug;8(8):1214-21

Impact of new task force criteria in the diagnosis of arrhythmogenic right ventricular cardiomyopathy. Giuseppe F. et al; International Journal of Cardiology 171 (2014) 179–183

Current and state of the art on the electrophysiologic characteristics and catheter ablation of arrhythmogenic right ventricular dysplasia/cardiomyopathy. Chung F-P, et al; J Cardiol (2015),

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jshibata

Editor in Chief of The Original Kings of County
EM/IM PGY4

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1 Comment

Ian deSouza · June 18, 2015 at 4:46 pm

Be careful with using amiodarone to treat an ACUTE ventricular tachydysrhythmia. Your cited reference cited actually states:

“in an observation study from North American ARVC Registry, Marcus et al. found that only amiodarone significantly reduced the risk of clinically relevant ventricular arrhythmias, while sotalol increased the risk of ventricular tachyarrhythmias and beta-blockers did not influence the risk.”

Even in the primary paper, the authors report that “those on amiodarone (n = 10) had a significantly lower risk of any clinically relevant ventricular arrhythmia (HR: 0.25, 95% CI: 0.07 to 0.95, p = 0.041.” Very small “n” and wide CIs almost inclusive of 1.

PREVENTION of ventricular dysrhythmias is very different than treatment of acute episodes. When ACUTE VT is examined as a whole, amiodarone is not very effective.