1 AFib reduces the ability of the atria to pump blood into the ventricles, and usually causes the heart to beat too rapidly. 2  One-half million new cases of atrial fibrillation are diagnosed every year in the U.S., and billions of dollars are spent annually on its diagnosis and treatment.
noun, (used with a singular verb) 1. the branch of mechanics that deals with the motion of air and other gases and with the effects of such motion on bodies in the medium. Compare aerostatics (def 1). Origin of aerodynamics.
Aerodynamics arose as an independent science at the beginning of the 20th century in connection with the demands of aviation. In this new field, a theory and methods were required for calculating the lift force of a wing, the aerodynamic drag of an aircraft and its parts and the thrust of a propeller.