Invasive hemodynamic tracing obtained during cardiac catheterization in a patient with hypertrophic cardiomyopathy (HCM) with left ventricular outflow tract (LVOT) obstruction

Shown are four surface ECG leads and the intracardiac pressure tracing obtained during cardiac catheterization. The systolic pressure in the left ventricle (LV) is 200 mmHg. When the catheter is pulled back to the LV outflow tract (LVOT), the LV systolic pressure falls to 100 mmHg, indicating that the pressure gradient across the LVOT is 100 mmHg. The aortic systolic pressure is also 100 mmHg, indicating that there is no gradient across the aortic valve.