The heart is a remarkable organ. It beats continuously, each and every minute of every day. The heart is made up of very specialized muscle tissue called "myocardium." This tissue is very resilient, it must be, in order to continuously work to provide nutrients to the body during a person's entire life. Though the heart is very strong, many people purposefully abuse it through the overuse of drugs and alcohol. Further harm to the heart occurs through poor diet, stress and lack of physical activity.