The heart is a hollow muscular pump that propels blood to the different parts of the body and is controlled by electrical signals generated within the heart itself. A number of heart conditions such as bradycardia, supraventricular tachycardia, syncope, heart failure and hypertrophic cardiomyopathy can disrupt these signals and cause an abnormal heart beat, which may be too slow, fast or irregular and can lead to fatigue, shortness of breath and fainting.