Exercise-induced ARVC is possibly a result of excessive right ventricular wall stress during high intensity exercise.

The nomenclature ARVD is currently thought to be inappropriate and misleading as ACM does not involve dysplasia of the ventricular wall.

ACM can be found in association with diffuse palmoplantar keratoderma, and woolly hair, in an autosomal recessive condition called Naxos disease, because this genetic abnormality can also affect the integrity of the superficial layers of the skin most exposed to pressure stress.

[6] If symptoms do occur, the initial presentation is often due to abnormal heart rhythms (arrhythmias) which in arrhythmogenic cardiomyopathy may take the form of palpitations, or blackouts.

Only 30% to 50% of individuals affected by ACM will test positive to one of the known genetic mutations in chromosomal loci associated with the disease.

Types include: In recent years, several studies have found that excessive long-term sports activity can cause exercise-induced arrhythmogenic right ventricular cardiomyopathy (EIARVC).

[35][36] In a 2003 study, 46 endurance athletes, mostly cyclists, presented with various symptoms suggestive of arrhythmia of RV origin.

The disease process starts in the subepicardial region and works its way towards the endocardial surface, leading to transmural involvement (possibly accounting for the aneurysmal dilatation of the ventricles).

This leads to thinning of the RV free wall (to < 3 mm thickness) Myocytes are replaced with fibrofatty tissue.

In this case, the EKG shows a left bundle branch block (LBBB) morphology with an inferior axis.

The differential diagnosis for the ventricular tachycardia due to ACM include: In order to make the diagnosis of ACM, a number of clinical tests are employed, including the electrocardiogram (EKG), echocardiography, right ventricular angiography, cardiac MRI, and genetic testing.

However, this is a non-specific finding, and may be considered a normal variant in right bundle branch block (RBBB), women, and children under 12 years old.

Ventricular ectopy seen on a surface EKG in the setting of ACM is typically of left bundle branch block (LBBB) morphology, with a QRS axis of −90 to +110 degrees.

Signal averaged ECG (SAECG) is used to detect late potentials and epsilon waves in individuals with ACM.

Findings consistent with ACM are an akinetic or dyskinetic bulging localized to the infundibular, apical, and subtricuspid regions of the RV.

False positives include other conditions with fatty infiltration of the ventricle, such as long-term excessive alcohol use and Duchenne or Becker muscular dystrophy.

A post mortem histological demonstration of full thickness substitution of the RV myocardium by fatty or fibro-fatty tissue is consistent with ACM.

This raises a clinical dilemma: How to prophylactically treat the asymptomatic patient who was diagnosed during family screening.

Prior to the decision of the treatment option, programmed electrical stimulation in the electrophysiology laboratory may be performed for additional prognostic information.

Goals of programmed stimulation include: Regardless of the management option chosen, the individual is typically advised to undergo lifestyle modification, including avoidance of strenuous exercise, cardiac stimulants (i.e.: caffeine, nicotine, pseudoephedrine) and alcohol.

Regarding physical activity and exercise, ARVC patients, as well as gene carriers of pathogenic ARVC-associated desmosomal mutations, should not participate in competitive sports.

These patients should be advised to limit their exercise programmes to leisure-time activities and remain under clinical surveillance.

If antiarrhythmic agents are used, their efficacy should be guided by series ambulatory Holter monitoring, to show a reduction in arrhythmic events.

Individuals with decreased RV ejection fraction with dyskinetic portions of the right ventricle may benefit from long term anticoagulation with warfarin to prevent thrombus formation and subsequent pulmonary embolism.

It may be indicated if the arrhythmias associated with the disease are uncontrollable or if there is severe bi-ventricular heart failure that is not manageable with pharmacological therapy.

While this is a genetically transmitted disease, individuals in their teens may not have any characteristics of ACM on screening tests.

Others may have symptoms and signs related to right ventricular failure, such as lower extremity edema, or liver congestion with elevated hepatic enzymes.

However, by the time the individual has signs of overt right ventricular failure, there will be histological involvement of the left ventricle.

[44] Based on these findings and other evidence, it is thought that in most patients, additional factors such as other genes, athletic lifestyle, exposure to certain viruses, etc.

In Italy, the prevalence is 40/10,000, making it the most common cause of sudden cardiac death in the young population.