Invasive hemodynamic tracing in a patient with HCM showing variable left ventricular outflow tract obstruction

Shown are four surface ECG leads (I, II, III, and V6) and simultaneous pressure tracings from the left ventricle (LV, arrow) and aorta (Ao, arrow). Although no change in heart rate occurs during this tracing, a spontaneous increase in the LV outflow tract obstruction and LV pressure is observed with the gradient increasing from 10 to 80 mmHg. The increase in gradient is associated with a narrowing of the aortic pulse pressure and the development of a spike-and-dome arterial configuration (SD, arrow).