Arrhythmogenic cardiomyopathy and sudden death in young athletes: causes, pathophysiology, and clinical features

Arrhythmogenic cardiomyopathy (AC) is a rare non-ischaemic cardiomyopathy with a prevalence in of 1:200 to 1:5000. In the 1980s, the disorder was demonstrated to be a major cause of sudden death (SD) in the young and athletes, thus emphasizing the need for early diagnosis for disqualification from sport activity. Pre-participation screening using ECG is effective in detecting ECG abnormalities which raise suspicion of the disease, requiring additional second- and third-level investigations to obtain a definite diagnosis. Cardiac magnetic resonance (CMR), which can detect both morpho-functional and tissue abnormalities, is probably the best tool for assessing doubtful cases. The rarer left ventricular variant (‘non-ischaemic left ventricular scar’) is not detected by ECG at first-level pre-participation screening, which presents a major challenge for SD prevention. Risk stratification consensus criteria recommend use of an implantable cardioverter defibrillator (ICD). Use of pre-participation screening and automated external defibrillators (AEDs), working together should help to prevent SD. Since at least 60% of cases are heredofamilial and usually present desmosome gene mutations, genetic investigation should be carried out in the proband and cascade genetic screening should be offered to first-degree family members for primary prevention. Basic research into the AC pathogenic mechanisms is in progress, and there is clinical and experimental evidence that exercise with right ventricular overload may favour onset and progression of AC, at least in genotype-positive patients. Reduction of sports activity will not only prevent abrupt onset of ventricular arrhythmias with the risk of SD, but may also delay phenotype expression.