The fundamental hypothesis of this project is that real-time intracardiac pressures can be monitored and quantified noninvasively in humans using a novel contrast-enhanced ultrasound technique called subharmonic-aided pressure estimation (SHAPE).This study will use contrast echocardiography to assess the accuracy of SHAPE compared to simultaneously acquired intracardiac pressures measured invasively during cardiac catheterization. This study is designed to verify that contrast echocardiography using the SHAPE method, already proven in a canine model and tested in a human pilot study can be used as a surrogate for cardiac catheterization with sufficient accuracy to allow clinical applicability in humans.