No abstract available
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Beds
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Contrast Media
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Echocardiography / methods*
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Heart Septal Defects, Atrial / diagnostic imaging*
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Humans
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Supine Position
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Valsalva Maneuver