Evolution of diagnostic methods and prediction of noncoronary ventricular arrhythmias
Nonischemic ventricular arrhythmias - special term that integrates rhythm disturbances arising from His bundle branches, Purkinje fibers, ventricular contractile myocardium and not associated with coronary artery disease. They constitute about 10-30% of the ventricular arrhythmias and have a significantly role in structure of mortality in younger patients. The most frequent causes of non-ischemic ventricular arrhythmias are various cardiomyopathy (13%), myocarditis (11%), congenital and acquired heart diseases (6%), mitral prolapse (3%), arrhythmogenic right ventricular dysplasia (5%) and genetically determined ion channelopathies (10%). In 52% of cases, routine methods of investigation do not identify the arrhythmogenic substrate. Nonischemic ventricular arrhythmias are the results of one of these mechanism: re-entry, abnormal automaticity, trigger activity. One of the most important risk factors for sudden cardiac death is reduced left ventricular ejection fraction. However, most patients with non-ischemic ventricular arrhythmias in risk-group for sudden cardiac death have preserved or moderately reduced left ventricular myocardial contractility. The search for new non-invasive markers of life-threatening arrhythmias in this category of patients is an important goal. Modern diagnostic methods provide valuable information for predicting arrhythmic events. This article discusses the possibility of tissue Doppler imaging and cardiac magnetic resonance with late gadolinium enhancement to identify the substrate and prediction of noncoronary ventricular arrhythmias. Using these diagnostic procedures in addition to the standard protocol surveys in some cases allow to optimize the treatment strategy, as well as the selection of patients for surgical correction of rhythm disturbances and implantation of cardioverter-defibrillators.