Late Phenotypic Expression of Hypertrophic Cardiomyopathy: When to Stop Looking?

Guidelines recommend clinical assessment, an electrocardiogram, and imaging every 3 to 5 years in adults who are genotype positive, phenotype negative for hypertrophic cardiomyopathy (HCM) or who have a first-degree relative with genotype-negative HCM. The age to stop screening is unclear. We report 4 cases of individuals transitioning from phenotype-negative to phenotype-positive HCM at various ages.