Final answer:
The second-line drug for wide complex tachycardias (arrhythmias) is amiodarone, a potassium channel blocker that helps restore a normal heart rhythm by affecting repolarization during the action potential.
Step-by-step explanation:
The second-line drug for wide complex tachycardias (arrhythmias) is amiodarone. It is a potassium channel blocker that is used to treat abnormal electrical activity in the heart. Wide complex tachycardias are a type of arrhythmia that have broad QRS complexes on an ECG, indicating the presence of abnormal electrical pathways in the ventricles.
Amiodarone works by blocking the movement of potassium ions through voltage-gated potassium channels, which affects repolarization during the action potential. By slowing down repolarization, amiodarone helps to restore a normal heart rhythm.
Other medications that may be used to treat wide complex tachycardias include procainamide and sotalol. These medications also work by blocking potassium channels and have similar effects on repolarization.