A pacemaker is a small device, about the size of a pocket watch, that`s placed under the skin near your heart to help control your heartbeat. People may need a pacemaker for a variety of reasons mostly due to one of a group of conditions called arrhythmias, in which the heart`s rhythm is abnormal. Normal aging of the heart may disrupt your heart rate, making it beat too slowly. Heart muscle damage resulting from a heart attack is another common cause of disruptions of your heartbeat. Some medications can affect the heart rate as well. For some, genetic conditions cause an abnormal heart rate. Regardless of the underlying cause of an abnormal heart rate, a pacemaker may fix it. A pacemaker can often be implanted in your chest with a minor surgery. You may need to take some precautions in your daily life after your pacemaker is installed.