Ventricular fibrillation is a cause of cardiac arrest and sudden cardiac death. The ventricular muscle twitches randomly, rather than contracting in a co-ordinated fashion (from the apex of the heart to the outflow of the ventricles), and so the ventricles fail to pump blood into the arteries and into systemic circulation. Ventricular fibrillation is a sudden lethal arrhythmia responsible for many deaths mostly brought on by ischaemic heart disease. Acute coronary syndrome (ACS) is a set of signs and symptoms related to the heart. ACS is compatible with a diagnosis of acute myocardial ischemia. This book presents current research from across the globe in the study of ventricular fibrillation and acute coronary syndrome, including clopidogrel response in acute coronary syndrome; primary ventricular fibrillation in "tako-tsubo" syndrome; and ECG predictors of fibrillatory events.