Midventricular Obstruction With Diastolic Paradoxic Jet Flow in Transthyretin Cardiac Amyloidosis: A Case Report.

Transthyretin (ATTR) cardiac amyloidosis has attracted clinical attention because of the development of practical identification and effective treatment. Since one of the initial manifestations of this condition is ventricular hypertrophy, the differential diagnosis includes hypertrophic cardiomyopathy (HCM). Midventricular obstruction (MVO) accompanied by paradoxic jet flow (PJF), which is an early diastolic flow from the apex to the base of the left ventricle, has been observed almost exclusively in HCM. Here, we report a case of ATTR cardiac amyloidosis with MVO and PJF. An 81-year-old woman presented with exertional dyspnea. Echocardiography showed biventricular hypertrophy, MVO with a peak flow velocity of 3.1 m/s in the mid-left ventricle, and PJF. A diagnosis of not HCM but wild-type ATTR cardiac amyloidosis was confirmed by cardiac biopsy and genetic analysis. This case highlights the importance of recognizing MVO along with PJF as a possible morphology in patients with ATTR cardiac amyloidosis.