Fainting, passing out, or medically called syncope, is a temporary loss of consciousness. Fainting can be caused by various reasons like dehydration, heavy workouts, pain, exhaustion and many more. This occurs when the blood pressure is very low and the brain doesn’t get the sufficient amounts of oxygen. Some certain severe heart problems can cause fainting. Patients with problems with the electrical system of the heart, known as tachycardia and bradycardia, have experienced fainting. Also, a valve problem may be an indicator, if there is a malfunction that stops the proper blood flow from going through the heart and preventing the brain to receive enough oxygenated blood.