Background: Cardiac amyloidosis (CA), following a non-invasive diagnosis, constitutes an increasingly prevalent heart failure (HF) etiology. This study aims to determine which echocardiography findings help to diagnose CA in patients with left ventricular hypertrophy (LVH) admitted for decompensated HF., Methods: The present study is a retrospective observational study on a cohort of 85 LVH patients admitted for HF decompensation, in which 99mTc-DPD scanning was performed to rule out transthyretin CA. The echocardiographic findings obtained were compared between CA and non-CA groups., Results: From a total number of 85 patients, 49 (57.6%) met the CA criteria and 36 (42.3%) were ruled out for the disease. Interventricular septum thickness (16 ± 3 mm vs. 14 ± 3 mm), left ventricular posterior wall thickness (14 ± 3 mm vs. 11 ± 2 mm), left ventricular mass (259 ± 76 g vs. 224 ± 53 g), left ventricular end-diastolic diameter (48 ± 7 mm vs. 53 ± 6 mm), left ventricular end-diastolic indexed volume (51 ± 18 cm3/m2 vs. 59 ± 16 cm3/m2), tricuspid annular plane systolic excursion (16 ± 5 mm vs. 20 ± 4 mm), right atrial area (27.4 ± 8.4 cm2 vs. 22.2 ± 5.7 cm2) and strain relative apical sparing (2.2 ± 0.9 vs. 1.03 ± 0.4; p = 0.04) were significantly associated with the diagnosis of CA., Conclusions: In patients with LVH admitted for HF decompensation, there are several echocardiographic features (LVH, reduced left ventricular cavity size, strain relative apical sparing, right atrial dilation, and altered right ventricular function) that are associated with the diagnosis of cardiac amyloidosis.