Abstract 3080: A 22-Year-Old Female With Non-Hypertrophic Hypertrophic Cardiomyopathy
A 22-year-old female presented with worsening dyspnea on exertion, fatigue, and abdominal distention. On examination, she had a jugular venous pressure >15 cm H2O with a prominent y-descent, rhonchorous breath sounds, a fluid wave and shifting dullness, and an S3, but no inducible systolic murmur or knock. The electrocardiogram showed atrial flutter with prominent F-waves and a ventricular rate of 85. A transthoracic echocardiogram revealed preserved biventricular systolic function with severe biatrial enlargement; no significant left ventricular (LV) hypertrophy. Doppler interrogation suggested advanced LV diastolic dysfunction. Cardiac MRI showed no pericardial thickening, but focal crypts within the LV inferoseptal wall contiguous with the LV lumen. There was marked delayed gadolinium enhancement in the mid-wall of the ventricular septum, sparing the endocardium. Hemodynamic study revealed elevated right and left sided-filling pressures, with a prominent y-descent, suggestion of a “dip-and-plateau,” and ventricular concordance. Myocyte hypertrophy with myofiber disarray and interstitial fibrosis were evident on right ventricular endomyocardial biopsy. Sequencing of select genes revealed mutations in MYL2 and MYL3 genes, affecting myosin light chains. This case highlights classic findings of restrictive physiology alongside characteristic histologic patterns and cardiac MRI findings associated with hypertrophic cardiomyopathy. Ultimately, this is the first case to describe multiple sarcomeric mutations, especially in myosin light chains, in a patient with restrictive physiology. Moreover, this case demonstrates the utility of multiple modalities, including genetic testing, to characterize a patient’s cardiomyopathy, which may affect both diagnosis and prognosis.