In neuromuscular disorders, the first step is often to assess the cause of the abnormal heart rate or rhythm and determine whether or not the conduction system itself is the primary problem. A referral to a cardiologist is often part of the assessment process. The doctor will listen to the heart with a stethoscope and probably order an EKG to see how the electrical system is behaving. The doctor may also request a special 24-hour EKG recording called Holter monitoring to see how the heart responds to different activities. More extensive studies can be done if needed.
Respiratory status is a factor.
If the person with the arrhythmia isn't breathing well because his respiratory muscles are weakening, this should be addressed, possibly with noninvasive assisted ventilation. General cardiac condition can affect conduction. Dietary factors, smoking and medications can play a role. Caffeine and tobacco can cause cardiac arrhythmias, particularly in people susceptible to them for other reasons, such as existing cardiac damage. A Anti-arrhythmic medications are mostly for tachyarrhythmias.