Most long-term effects are related to the cause. For example, rapid heartbeat due to anxiety or exercise often goes away quickly and has no long-term effects. Rapid heartbeat due to an arrhythmia or sepsis may sometimes result in death. A rapid heartbeat is not contagious and poses no risks to others. If the cause of the rapid heartbeat is an infection, the infection may be contagious.
Treatment is directed at the cause.
For example, someone who is dehydrated can be given fluids. A person with a fever may be given acetaminophen. Someone with an infection may need antibiotics or surgery. An individual with an arrhythmia may need heart medications to slow the heart rate, such as atenolol or lidocaine. Potential side effects depend on the treatments used.