Abstract 1121: It’s All in the Family: A Treatable Cause of Late-Onset Hypertrophic Cardiomyopathy

Abstract

A 73-year-old woman with a history of hypertension (HTN) and mild aortic insufficiency (AI) presented to clinic with progressive dyspnea, fatigue and decreased functional capacity. Her family history was remarkable for a 45-year-old son with a “weak heart” and kidney dysfunction that was being evaluated. Her physical exam was unremarkable with the exception of bradycardia. ECG revealed sinus bradycardia of 46-bpm and a complete RBBB. Transthoracic echo revealed a small cavity with severely increased wall thickness, with obliteration in systole, with no obstruction and mild AI; notably without a history of poorly controlled HTN or significant valvular disease. A right heart catheterization revealed low output failure with a FICK cardiac index of 1.9 L/min-m2. Of note, her son’s work-up revealed Fabry’s disease, with cardiac and renal involvement. Her alpha-galactosidase enzyme levels were low-normal. A cardiac MRI with late gadolinium enhancement revealed a pattern of fibrosis suggestive infiltrative disease, and atypical for HOCM. Endocardial biopsy demonstrated myelin figures with curvilinear bodies in multiple myocytes on ultrastructural examination, diagnostic for cardiac Fabry’s disease. Enzymatic replacement therapy was initiated and a DDD pacemaker was placed with improvement of her NYHA class and BNP level. A treatable disease, representing up to 4% of late-onset hypertrophic cardiomyopathy (HCM), Fabry’s disease should be considered when evaluating patients with non-obstructive HCM. Keys to establishing this diagnosis lay in integrating clinical, genetic, and imaging data and recognizing Fabry’s disease as an X-linked dominant (not recessive) disease that may have isolated cardiac involvement, in heterozygous females, despite low-normal alpha-galactosidase activity.