If you are undergoing any type of surgery involving anaesthetics, it is very important for you to notify the anaesthetist that you have a neuromuscular disorder. This is because many of the gases and chemicals used in anaesthetics affect both muscle and nervous tissue, including the heart.
Informing the anaesthetist of your diagnosis should be done regardless of how mild or severe your symptoms. Ideally, the anaesthetist should be told well in advance of the operation, so that tests can be carried out (if necessary) and proper care can be arranged.
From the American College of Chest Physicians (published in Chest, 2007)
From the Myotonic Dystrophy Foundation toolkit.