Extract

Comprehensive cardiac evaluation was performed on a 75-year-old African American woman referred to our hypertrophic cardiomyopathy (HCM) centre for refractory diastolic heart failure. The patient carried a diagnosis of non-obstructive HCM for several years and had a daughter with a diagnosis of HCM. A 12-lead electrocardiogram (Panel A) showed sinus bradycardia without left ventricular (LV) hypertrophy. Transthoracic echocardiogram (Panels B–D, see Supplementary data online, Videos S1S4) showed thickened LV (anterior septum 23 mm, posterior septum 30 mm) without any resting or provocable LV outflow obstruction and abnormal global longitudinal strain (−13%) with relative apical sparing. Additional imaging with cardiac magnetic resonance imaging (Panels E–G) demonstrated substantial, patchy, and mid-myocardial delayed enhancement (25% of the myocardium, arrows, Panel G). The myocardium was notably difficult to null. Given the available information, infiltrative cardiomyopathy was suspected (amyloid), and a subsequent 99mTc-pyrophosphate scan suggested cardiac amyloidosis [heart/contralateral [CL] counts >1.5; Panels H (1 h) and I (3 h)]. Endomyocardial biopsy and Congo red stain (Panels J and K) confirmed amyloid fibrils infiltrating the myocardium. Genetics for HCM panel subsequently demonstrated a typical mutation for amyloidosis in African Americans [heterozygous for pathogenic Val122Ile mutation in transthyretin (TTR) gene].

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