Up to one third of sudden deaths in "structurally normal hearts" may harbor a genetic defect related to a channelopathy (e.
g. Lqts, cpvt, brs, sqts). Cardiomyopathies can result in sudden death even when the structural anomalies are minimal (e.g. Arvc or hcm related to mutations in the tnnt2 gene). Genetic testing
is possible for these conditions but yield is <25%. Lqts is the only "good" test.