What are some causes of rapid heartbeat?

Causes of rapid heartbeat include a heart attack, changes to the heart's structure, high blood pressure and scarring found in the heart tissue, explains Mayo Clinic. People who have diabetes, high blood pressure, an underactive or overactive thyroid gland, and blocked arteries may also experience a rapid heartbeat.

Lifestyle habits such as smoking, drug abuse and drinking too much alcohol or caffeine can lead to a rapid heartbeat, warns Mayo Clinic. People taking certain prescription medications or herbal treatments and dietary supplements are at risk for increasing the rate of the heart. Air pollution and electrical shock increase the heart rate as well as stress.