About this study
1. Determine the feasibility of measuring velocity of flow across a patent foramen ovale and using this Doppler spectrum to estimate left atrial pressures.
2. Correlate PFO velocity Doppler profile with the degree of diastolic dysfunction.
3. To Correlated PFO velocity and Doppler derived left atrial pressure with left atrial pressure measured during cardiac catheterization in a subset of (n=20) subjects for validation of this methodology.