arrhythmia
"I've been taking the maximum dose for years to control atrial fibrillation and flutter. It reduced the atrial fibrillation from 100% of the time to about 65% - which feels WAY better. I accidentally overdosed (double dose) once and went to ER for observation with NO ill effects. Later learned that another person - same situation - DIED within a couple of hours. Glad thay told me that after. This medicine is great, POWERFUL and dangerous if overdosed. So if you take it be damned sure to never ever take more than prescribed. "