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.
Small inflatable and plastic pools are typically filled with tap water. Some people in the United States have a disinfectant in their tap water but this is not adequate to kill germs that may get into water used for swimming. Sources of information exist about how to disinfect these pools.