A – S syndrome, or cardiogenic ischemic syndrome, is a sudden onset of severe, fatal slow or rapid arrhythmias that cause a sharp decrease in blood output from the heart in a relatively short period of time, producing symptoms such as severe cerebral ischemia, loss of consciousness, and syncope. A – S syndrome is a group of clinical syndromes of acute cerebral ischemic attacks caused by sudden changes in heart rate, independent of changes in body position, often due to sudden severe tachycardia, or sudden severe bradycardia, resulting in syncope. Its common causes are tachyarrhythmias, slow arrhythmias, acute blockage of cardiac blood displacement and some congenital heart diseases.