ICD-11

These are myocardial disorders in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.

Arrhythmogenic ventricular cardiomyopathy is a cardiomyopathy characterised by myocardial cell loss with partial or total replacement of right ventricular muscle by adipose and fibrous tissue, beginning subepicardially to become transmural in time, sparing the papillary muscles and trabeculae, and often associated with aneurysms particularly of the right ventricular outflow tract. There is progressive systolic impairment with ventricular dilation and marked propensity for ventricular arrhythmias of right, as well as left, ventricular origin. Classically a disease of the right ventricle, more recent evidence suggests left ventricular involvement to a varying extent in up to 75% of cases, as well as isolated left ventricular disease.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a heart muscle disease clinically characterized by life-threatening ventricular arrhythmias. Its prevalence has been estimated to vary from 1:2,500 to 1:5,000. ARVC/D is a major cause of sudden death in the young and in athletes. The clinical picture may include: a subclinical phase without symptoms and with ventricular fibrillation being the first presentation; an electrical disorder with palpitations and syncope, due to tachyarrhythmias of right ventricular origin; right ventricular or biventricular pump failure, so severe as to require transplantation. The pathology consists of a genetically determined dystrophy of the right ventricular myocardium with fibro-fatty replacement to such an extent that it leads to right ventricular aneurysms. The causative genes (ACTN2, DSC2, DSG2, DSP, JUP, TMEM43, LDB3, PKP2, RYR2, TGFB3) encode proteins of mechanical cell junctions (plakoglobin, plakophilin, desmoglein, desmocollin, desmoplakin) and account for intercalated disk remodeling. Familial occurrence with an autosomal dominant pattern of inheritance and variable penetrance has been reported. Recessive variants associated with palmoplantar keratoderma and woolly hair (see these terms) have also been described. Clinical diagnosis may be achieved by demonstrating functional and structural alterations of the right ventricle, depolarization and repolarization abnormalities, arrhythmias with the left bundle branch block morphology and fibro-fatty replacement through endomyocardial biopsy. Two-dimensional echocardiography, angiography and magnetic resonance are the imaging tools for visualizing structural-functional abnormalities. Electroanatomic mapping is able to detect areas of low voltage corresponding to myocardial atrophy with fibro-fatty replacement. The main differential diagnoses are idiopathic right ventricular outflow tract tachycardia, myocarditis, dilated cardiomyopathy and sarcoidosis (see these terms). Management revolves around palliative therapy and consists of antiarrhythmic drugs, catheter ablation and implantable cardioverter-defibrillators (ICDs). Young age, family history of juvenile sudden death, QRS dispersion greater than or equal to 340 ms, T-wave inversion, left ventricular involvement, ventricular tachycardia, syncope and prior cardiac arrest are the major risk factors for an adverse prognosis. Preparticipation screening for sport eligibility has been proven to be effective in detecting asymptomatic patients and sport disqualification has been life-saving, substantially decreasing the number of cases of sudden death in young athletes.