Atrial fibrillation and a corresponding enlargement of the left atrium may cause an increase in size of the mitral valve annulus. With a sinus rhythm, the mitral annulus undergoes dynamic changes during the cardiac cycle. For example, at the end of diastole the annular area is smaller than at the end of systole.
To determine who can perform aquatic therapy, we must define what aquatic therapy is. First, notice that aquatic therapy is considered a therapeutic procedure, not a modality. There are many technical and practical distinctions between the practice of aquatic therapy and the application of therapeutic modalities.
A swimming pool, swimming bath, wading pool, or paddling pool is a structure designed to hold water to enable swimming or other leisure activities. Pools can be built into the ground (in-ground pools) or built above ground (as a freestanding construction or as part of a building or other larger structure), and are also a common feature aboard ocean-liners and cruise ships.