One of the most important considerations in the acute management of atrial fibrillation is the need for anticoagulation (see the image below). Acute cardioversion for AF carries a risk of thromboembolism unless anticoagulation therapy is initiated prior to the procedure and continued post procedure.
The glass fibers are made of various types of glass depending upon the fiberglass use. These glasses all contain silica or silicate, with varying amounts of oxides of calcium, magnesium, and sometimes boron.
Those materials include glass-fiber (of course), cloth (cotton or man-made), carbon-fiber, non-woven glass or carbon mat, coir (a coconut fiber), modal (beech tree fiber), bamboo, and even hemp fiber. In truth what most people call fiberglass is properly referred to as Fiber Reinforced Plastic (FRP). It is a composite material, much like Carbon Fiber Reinforced Plastic (CFRP) so popular today, but FRP predates carbon fiber by at least seventy years.