Defining the interaction between exercise and arrhythmogenic right ventricular cardiomyopathy.

Abstract

gaverisetothepopularhypoth-esisthatexerciseactedasatriggerforarrhythmicevents.However,recentpre-clinicalandepidemiologicalinvestigationshaveassoci-atedintenseendurancewithearlieronsetandmoresevereexpres-sionoftheARVCphenotype,therebyimplyingthatexercisenotonlyactsasatriggerforarrhythmiasbutmayalsoimpactdirectlyonthediseasesubstrate.Arrhythmogenic right ventricular cardiomyopathy is a familialcardiomyopathy associated with abnormalities in the structure,function, and electrophysiological properties of the myocardium.A familial history or mutation in one of five desmosomal genescan be identified in a majority of ARVC patients, but there isconsiderable phenotypic variability such that the same mutationmay cause severe heart failure and arrhythmias in one patientand no symptoms in another. The reasons for this variabilityare incompletely understood, but hypotheses include additionalgenetic factors such as modifier polymorphisms or interactionwithenvironmentalfactors.Similarly,mutationsinnovelgenesorcomplexinteractionsbetweenpolymorphismsandenvironmentalfactors could also potentially explain the 30–40% of patients inwhom a familial predisposition cannot be currently identified. Inregard to potential environmental factors determining pheno-typicexpression,exerciseisalogicalcandidate.Intenseexerciseincreasesventricularwallstressanddisproportionatelyaffectsthe