• Acute coronary syndrome
• myocardial fibrosis
• cardiomyopathy hypertrophic
• cardiomyopathy
• hypertensive heart disease
• aortitis
• dissection
• atherosclerosis
• myocarditis
• chronic lung disease

To the Editor We read with interest the article by Garcia-Pavia et al1 published in Heart. The authors found desmosomal gene mutations typically associated with arrhythmogenic right ventricular cardiomyopathy (ARVC) in explanted hearts of patients with advanced idiopathic dilated cardiomyopathy (DCM). This study extends the findings of Elliott et al,2 who found desmosomal mutations in patients with familial DCM, by including histological assessment of fibrofatty change, the pathological hallmark of ARVC. The authors found no correlation between desmosomal mutations and fibrofatty change in the explants of their patients with DCM, thus challenging the histological criteria for the diagnosis of ARVC.1 We suggest that the causatory link between desmosomal mutations and ARVC also needs to be challenged or at least re-evaluated.

The presence of fibrofatty change in DCM has been reported previously.3 Furthermore, we have found lethal desmosomal mutations in sudden death victims without the pathological features of ARVC.4 Therefore, as corroborated by the article of Garcia-Pavia et al,1 it appears that the link between fibrofatty change and desmosomal alterations is becoming increasingly weaker. We could abandon fibrofatty change as a diagnostic finding for ARVC and define the entity by mutational analysis. Alternatively, we could continue to classify ARVC as cardiomyopathy with fibrofatty change (defined strictly with clear intermingling of fat, collagen and degenerated myocytes), accept that there are various morphological expressions including DCM and abandon the notion that desmosomal mutations define the disease. An analogy could be made with hypertrophic cardiomyopathy, which continues to be defined by phenotype as opposed to genotype, because of the non-specificity of sarcomeric mutations. More studies of desmosomal mutations in cardiac diseases other than ARVC and DCM are necessary in order to establish a definite link between ARVC and the desmosome.