Enlarged Image for Hypertrophic Cardiomyopathy

Invasive hemodynamic tracing obtained in a patient with severe resting left ventricular outflow tract gradient that is nearly abolished with the onset of dual-chamber pacing (double arrow). Note also the improvement in left atrial pressure at the onset of pacing. Ao = ascending aortic pressure, LA = left atrial pressure, LV = left ventricular pressure.