This chapter provides detail description of cardiology. Causes and effects of Congenital cyanotic heart disease, tricuspid atresia, Fallot’s tetralogy, ischemic chest pain, angina, myocardial infraction, pericardial effusion, infective endocarditis, congestive cardiac failure, hypertension, atrial fibrillation, pericarditis are given in detail. 11 tables are included to highlight difference between myocardial infraction and pulmonary infraction, difference between congenital AV fistula and acquired AV fistula, difference between dilated cardiomyopathy and hypertrophic cardiomyopathy, difference between aortic stenosis and idiopathic hypertrophic subaortic stenosis, difference between isotonic and isometric, mitral stenosis and mitral incompetence, arterial pulsation and venous pulsation.