Final answer:
The first line pharmacotherapy for congenital long QT syndrome is beta-blockers. If a patient cannot tolerate beta-blockers or symptoms persist, potassium channel blockers may be used. Other drugs like ciprofloxacin and azithromycin are not used to treat long QT syndrome.
Step-by-step explanation:
The first line pharmacotherapy for congenital long QT syndrome typically involves beta-blockers, which are considered the standard treatment. They work by reducing the heart rate and the risk of arrhythmias. In cases where patients cannot tolerate beta-blockers or continue to experience symptoms, other treatments such as potassium channel blockers may be considered. Potassium channel blockers, like procainamide, work by affecting the action potentials in the heart, slowing the rate at which the heartbeats. It's important to note that while the above-mentioned drugs such as ciprofloxacin and azithromycin can have cardiac-related side effects, they are not used in the treatment of long QT syndrome.