Cardiology is the branch of medicine, which studies the functioning of the heart and the circulatory system and any disruption in their normal functioning. The prevention, diagnosis and treatment of heart disorders such as hypertension, cardiac arrest, coronary artery disease and congenital heart defects are within the scope of this field. Various diagnostic tests are used for identifying the heart conditions relative to a healthy and an unhealthy heart function. Electrocardiogram, event monitor, Holter monitor, electrophysiology study and cardiac stress testing are used to monitor the electrical activity of the heart, detect rhythm abnormalities and assess cardiac function. Various techniques are used for cardiac imaging such as coronary catheterization, intravascular ultrasound, echocardiogram, among others. This book is a compilation of chapters that discuss the most vital concepts and emerging trends in the field of cardiology. From theories to research, case studies related to all clinical topics of relevance to this field have been included herein. This book on cardiology is a collective contribution of a renowned group of international experts.