How does quinidine, procainamide, and disopyramide treat atrial fibrillation?

Variable: These medications are older antiarrythmics that have been around for decades and may suppress af. They must be used very cautiously and only by very experienced cardiologists, due to their potential to actually cause potentailly life threatening ventricular arrythmias in certain patients - called a pro-arrthymic effect..Newer medications have been shown to be both safer and more effective.

Slow conduction: These medications, known as class i antiarrhythmics, work by blocking sodium channel conduction in the heart. This causes cardiac excitation to progress more slowly, hopefully preventing the formation of the driving force behind atrial fibrillation.