This chapter mainly focuses on the heart disorders, which includes heart failure, ischemic heart disease, myocardial infarction, valvular heart disease, rheumatic fever and rheumatic heart disease, infective endocarditis, noninfected vegetations, carcinoid heart disease, complications of prosthetic valves, cardiomyopathy, congenital heart disease, pathology of pericardium. Cardiovascular system consists of heart and blood vessels. The heart pumps the blood into the arterial tree and receives blood from venous circulation. Normal heart weighs about 250–350 g in an adult. It is a two-sided pump having four chambers upper two atria (right and left) and the lower two ventricles (right and left). The heart contracts at the rate ranging from 60–80 beats per minute. During systole, the heart contracts and relaxes during diastole. 10 well-illustrated figures are also presented in this chapter. A well-illustrated flowchart on mechanism of heart failure is also given in this chapter, which is very helpful for students or readers.