Hypertrophic Cardiomyopathy (HCM) with POCUS + Left Ventricular Outflow Tract Obstruction (LVOTO) Explained!

Diagnosing hypertrophic cardiomyopathy (HCM) via ultrasound requires identifying focal wall thickening and intraventricular obstruction, specifically within the left ventricular outflow tract (LVOT). Diagnostic criteria include a wall thickness of at least 15 mm, or 13 mm in patients with a family history of the condition, alongside an interventricular septum to posterior wall ratio exceeding 1.3 in normotensive patients. Beyond muscle growth, HCM often involves mitral valve abnormalities such as prolonged chordae or papillary muscle displacement. The Venturi effect frequently causes systolic anterior motion (SAM) of the mitral valve, which can be visualized using M-mode ultrasound. Furthermore, continuous wave Doppler through the apical five-chamber view reveals a characteristic "shark fin" waveform and elevated LVOT pressure gradients; a peak gradient greater than 30 mmHg serves as a diagnostic marker, while values over 50 mmHg indicate significant hemodynamic obstruction.