Letter by Denham et al Regarding Article, "Familial Occurrence of Atrioventricular Nodal Reentrant Tachycardia".

To the Editor: Michowitz et al present an interesting study on the prevalence of familial atrioventricular nodal reentrant tachycardia (AVNRT). They report a prevalence of 127 out of 10 000 of familial AVNRT with a likely autosomal dominant pattern of inheritance (with incomplete penetrance). A potentially important question is whether all the observed cases represent “pure” familial AVNRT or whether a proportion form part of complex phenotypes associated with conditions such as Brugada syndrome. Interestingly, Hasdemir et al previously reported a 27% prevalence of drug-induced Brugada ECG changes in patients presenting with AVNRT. These findings suggest that patients with Brugada syndrome are enriched in populations with AVNRT. Future studies with more detailed phenotyping of patients presenting with familial AVNRT would be of interest to determine the relative contribution of concealed Brugada syndrome. Disclosures