Final answer:
Procainamide is a potassium channel blocker used to treat tachycardia with wide complexes by delaying repolarization and prolonging the action potential, leading to a slow down in heart rate. It is administered intravenously in stable cases of tachycardia to restore normal heart rhythm.
Step-by-step explanation:
Potassium channel blockers, such as procainamide, are essential in treating specific types of cardiac dysrhythmias, including tachycardia with wide complexes. These medications work by impeding the movement of potassium (K+) ions through voltage-gated K+ channels. During an action potential, potassium channels are primarily involved in the repolarization phase, where they allow K+ to exit the cell, returning the membrane potential back to its resting value. The use of potassium channel blockers can delay repolarization, thereby prolonging the action potential and refractory period. This effect can be particularly beneficial in the treatment of tachycardia, as it helps to slow down the heart rate by decreasing the rate at which succeeding action potentials can be generated.
In the specific scenario of stable tachycardia with wide complexes, procainamide is administered intravenously to restore a normal heart rhythm. The goal is to manage the rapid and abnormal heart rhythm without causing excessive delays in cardiac conduction or refractoriness that could lead to bradycardia or asystole.