The Coanda effect in cardiology

Many of the current technologies used today in clinical practice owe their lives to physicians. Coanda effect was originally described by the romanian scientist as a phenomenon with application in aerodynamics, the main field of interest for Henri Coanda. He made the observation that a thin liquid jet, passing through a narrow channel which is followed by a curved surface, deviates according to the surface shape, adhering to it. The description of the phenomenon and a possible explanation was found in a patent registrated in France, in 1934. It is interesting how a physical phenomenon described 70 years ago has found its clear demonstration and real time visualization on color Doppler flow mapping. Coanda effect influences jet size and color encoding, determining (for eccentric jets) smaller color Doppler jet areas, greater variance and reverse velocity encoding. The phenomenon may alter the interpretation of color Doppler images and needs to be taken into account for an appropriate echocardiography assessment of valvular regurgitation and other abnormal flows.