Some symptoms of a slow heartbeat, or bradycardia, are fainting or near-fainting, weakness, shortness of breath, fatigue and chest pains, according to Mayo Clinic. The person might also feel dizzy, have problems remembering and grow quickly tired during physical exertion.
Rarely, the person experiencing a slow heartbeat might go into cardiac arrest, explains the American Heart Association. Other complications are chest pain and high blood pressure. The reasons for a slow heart rate might include problems with the heart's pacemaker or abnormalities in the electrical signals in the heart. The person might also be suffering from diseases such as hypothyroidism, and his heart might be damaged from disease.
Other causes of a slow heartbeat are congenital disorders, high blood pressure, obstructive sleep apnea, too much iron in the blood and medications, notes Mayo Clinic. If the slow heartbeat is dangerous or has lasted a long time, it is useful to treat the underlying cause. Some people have a pacemaker installed to regulate their heartbeat, especially if there is something wrong with the heart's electrical system, states WebMD.
A slow heartbeat is considered to be beneath 60 beats per minute when the person is at rest, according to Mayo Clinic and the American Heart Association. However, a slow heartbeat is normal for some people.