7th March 2024

Arrhythmogenic Right Ventricular Cardiomyopathy

Pathology

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is perhaps the simplest of the cardiomyopathies to describe as it has one common pathology – there is progressive replacement of myocardial tissues with adipose tissue, typically in the right ventricular inflow, outflow and apex leading to the name.  This leads to a particular morphology with dilation and aneurysm of the right ventricle, best seen on echo or particularly MRI, but with characteristic changes also seen on ECG.

It can also occur in the left ventricle, where a DCM phenotype is more commonly seen.

It is exclusively genetic, largely caused by autosomal dominant genes encoding proteins in the cardiomyocyte desmosome, although it is also seen in some autosomal recessive conditions such as Naxos and Carvajal syndromes.

Signs and symptoms 

ARVC generally presents with palpitations or syncopal symptoms, though sudden death caused by right ventricular arrhythmias can be the first symptom of the disease.

It has three typical phases – concealed phase, electrical disorder then RV failure.

In the concealed phase, there may be no significant symptoms and sudden death in the context of intense exercise may occur in this phase.

In those with an overt electrical disorder there may be palpitations, presyncope or syncope due to ventricular arrhythmias.

Those with RV failure will see some of the typical signs and symptoms of ‘right-sided’ heart failure – peripheral oedema, ascites, elevated JVP and hepatic congestion with hepatomegaly.

Ultimately, this can progress and left ventricular involvement can lead to biventricular failure and a similar picture to a dilated cardiomyopathy.

Investigations

ARVC is commonly diagnosed through imaging modalities requested as a result of suspicious ECG findings or symptoms.

Typical ECG features will include T wave inversion in V1-V3, QRS widening in V1-V3 and frequent ventricular ectopics. The most specific finding is that of an epsilon wave – a small deflection at the end of the QRS complex which represents post-excitation of the RV myocytes.

Echocardiography will typically demonstrate RV outflow tract dilation and reduction in RV fractional area change (a similar measure to ejection fraction in the LV but measured in one plane rather than two)

Cardiac MRI is very useful in demonstrating the underlying pathology, with RV enlargement and thinning, fatty infiltration and fibrosis of the wall.

If there is a suspicion of familial inheritance then genetic testing can be performed to identify the genetic abnormality and genetic counselling should be offered to first degree family members.

Treatment

Heart failure in the context of ARVC should be treated as per guidelines with optimal medical therapy as described above for DCM.

In the context of relatively low levels of electrical abnormalities, antiarrhythmic beta blockers such as sotalol or amiodarone are effective at controlling arrhythmias.

For patients with episodes of sustained VT or any episodes of VF, drugs can be trialed to reduce their likelihood, with EP studies to assess for continued inducibility of malignant arrhythmias. In certain patients, catheter ablation can also be considered.

For those in whom these arrhythmias remain inducible, those with overt arrhythmias outside of the EP setting, or in those with severe systolic dysfunction of either ventricle, an implantable cardiac defibrillator is typically required and is effective in preventing arrhythmogenic sudden death.

As per DCM, patients with end-stage heart failure may need consideration for device therapy or transplantation.

References

• https://www.heartrhythmjournal.com/article/S1547-5271(19)30438-2/fulltext
• https://www.bsecho.org/common/Uploaded%20files/Education/Protocols%20and%20guidelines/ARVC.pdf
• https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-8/Takotsubo-cardiomyopathy