Electrical heart diseases: the new challenge in cardiology
The distinction between heart attack and sudden cardiac death is not definite for the scientific community. The heart attack or myocardial infarction consists in the occlusion of a coronary artery which can determine ischemia and necrosis of the myocardial muscle. The evolution of heart attack is extremely variable from a totally asymptomatic one to sudden cardiac death. Due to the amazing development in the field of cardiovascular prevention and in the treatment of myocardial infarction, the heart attack is a manageable issue in clinical setting.
The sudden cardiac death (SCD) is a very tragic situation in which a previously asymptomatic individual suddenly collapses dead. For a cardiologist SCD usually implies a malignant ventricular arrhythmias (ventricular fibrillation or ventricular tachycardia) occurring with little or no warning.
In some cases the ventricular arrhythmias (VA) can result from ischemia during myocardial infarction or in the setting of a healed myocardial infarct with scar. Also a large number of non ischemic patients with a structural heart disease (dilated cardiomyopathy, right ventricular dysplasia and hypertrophic cardiomyopathy) can experience SCD. Recently the occurrence of malignant VA has consistently been noticed in patients with a structurally normal heart but with an alteration in the ion channel of the myocytes membrane also named channelopathies (Brugada, short QT, long QT syndrome).
SCD represents a real challenge for the cardiology community. Currently non invasive tests are not able to predict the occurrence of VA. The therapeutic option available is an implantable cardiac defibrillator. However only a limited number of the large cohort of patients will utilize the device while a large number of patients who do not meet the implantation criteria will die of a sudden cardiac death. Recently, the development of a system able to delineate an electro-anatomical 3D map of heart chambers allows the percutaneous treatment of malignant VA through percutaneus radiofrequency catheter ablation. However, the outcome of the procedure is still not satisfactory. An integrated approach to the evaluation of the recorded intracardiac signal can provide insight in the pathogenesis of VA and provide new pathways for the prevention and treatment of SCD.