Cardiac AL amyloidosis in a veteran endurance athlete with pre-existing apical hypertrophic cardiomyopathy: a case report.

Background: Patients with mild phenotypes of chronic cardiomyopathies are often followed up over time, and there is a temptation to assume a change in symptom status or investigation results is due to the original pathology. The possibility of acquired pathology must be considered in these patients. Case summary: We present a case of a middle-aged veteran endurance athlete followed up for a mild phenotype of apical hypertrophic cardiomyopathy originally picked up due to an asymptomatic abnormal electrocardiogram (ECG). He developed subtle symptoms and morphological changes in his investigations (ECG, echocardiography, exercise tolerance test (ETT), and magnetic resonance imaging (MRI)). Due to the previously quiescent phenotype, a diagnosis of coexistent amyloid light-chain (AL) cardiac amyloidosis secondary to IgA lambda multiple myeloma was made. Discussion: This case underscores the importance of paying attention to subtle changes in symptoms and morphology when managing patients with mild phenotypes and athletes, and considering alternative pathology when these occur. Multimodality imaging is essential in the investigation of such patients.