cardiac rhythm disease cardiogenetic disease cardiac conduction disease with or without cardiomyoopathy OMIMPS:616117 hereditary atrial tachyarrhythmia-infra-Hisian cardiac conduction disease MONDO:0980715 Orphanet:436242 A rare genetic cardiac disease characterized by variably expressed atrial tachyarrhythmia (such as atrial flutter, paroxysmal or chronic atrial fibrillation, ectopic atrial tachycardia, or multifocal atrial tachycardia), infra-Hisian conduction system disease, and vulnerability to dilated cardiomyopathy. Age of onset ranges between childhood and adulthood.