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Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) was initially recognized as a clinical entity by Fontaine and Marcus, who evaluated a group of patients with ventricular tachyarrhythmia from a structurally impaired right ventricle (RV). Since then, there have been significant advances in the understanding of the pathophysiology, manifestation and clinical progression, and prognosis of the pathology. The identification of genetic mutations impairing cardiac desmosomes led to the inclusion of this entity in the classification of cardiomyopathies. Classically, ARVC/D is an inherited disease characterized by ventricular arrhythmias, right and / or left ventricular dysfunction; and fibro-fatty substitution of cardiomyocytes; its identification can often be challenging, due to heterogeneous clinical presentation, highly variable intra- and inter-family expressiveness, and incomplete penetrance. In the absence of a gold standard that allows the diagnosis of ARVC/D, several diagnostic categories were combined and recently reviewed for a higher diagnostic sensitivity, without compromising the specificity. The finding that electrical abnormalities, particularly ventricular arrhythmias, usually precede structural abnormalities is extremely important for risk stratification in positive genetic members. Among the complementary exams, cardiac magnetic resonance imaging (CMR) allows the early diagnosis of left ventricular impairment, even before morpho-functional abnormalities. Risk stratification remains a major clinical challenge, and antiarrhythmic drugs, catheter ablation and implantable cardioverter defibrillator are the currently available therapeutic tools. The disqualification of the sport prevents cases of sudden death because the effort can trigger not only the electrical instability, but also the onset and progression of the disease.

In patients needing a pacemaker (PM) for bradycardia indications, the amount of right ventricular (RV) apical pacing has been correlated with atrial fibrillation (AFib) and heart failure (HF) in both DDD and VVI mode. RV pacing was linked with left ventricular (LV) dyssynchrony in almost 50% of patients with PM implantation and atrioventricular (AV) node ablation for AFib. In patients with normal systolic function needing a PM, apical RV pacing resulted in LV ejection fraction (LVEF) reduction. These negative effects were prevented by cardiac resynchronization therapy (CRT). Algorithms favoring physiological AV conduction are possible useful tools able to maintain both atrial and ventricular support and limit RV pacing. However, when chronic RV pacing cannot be avoided, it appears necessary to reconsider the cut-off value of basic LVEF for CRT. In HF patients, RV pacing can induce greater LV dyssynchrony, enhanced by underlying conduction diseases. In this context, a more deleterious effect of RV pacing in implantable cardioverter-defibrillator (ICD) patients with low LVEF can be expected. In some major ICD trials, DDD mode was correlated with increased mortality/HF. This negative impact was attributed to unnecessary RV pacing >40-50%, virtually absent in VVI-40 mode. However, some data suggest that avoiding RV pacing may also not be the best option for patients requiring an ICD. In patients with impaired LV function, AV synchrony should therefore be ensured. The best pacing mode in ICD patients with HF should be defined on an individual basis., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)