Cardiologists diagnoses and treats many heart conditions, including many rare and complex disorders.  Multidisciplinary teams of experts are trained in many heart conditions, including heart valve disease; coronary artery disease; congenital heart disease in adults and congenital heart defects in children, such as Ebstein's anomaly and hypoplastic left heart syndrome; hypertrophic cardiomyopathy; heart failure; and heart rhythm disorders (arrhythmias).