Electroanatomic mapping-guided endomyocardial biopsy in patients with apparently idiopathic ventricular arrhythmias.

The management of ventricular arrhythmias (VA) in the presence of an apparently normal heart represents a major clinical challenge and a main field of clinical research. In the past years, new imaging techniques and the spreading of new generation genetic testing have improved our knowledge of the pathogenesis of apparently idiopathic VA. However, in the absence of specific recommendations, the type and the number of noninvasive and invasive studies necessary to rule out a possible underlying cause of VA or sudden cardiac death remain extremely variable. Therefore, in many patients the underlying cardiac disease is not recognized, and a possible specific therapeutic approach cannot be initiated. Endomyocardial biopsy (EMB) can provide a significant contribution to the identification of myocardial disorders causing VA but has never been definitively included in the routine diagnostic work-up of these patients due to the possible sampling error particularly in disorders with a focal or patchy distribution. Three-dimensional electroanatomic mapping (EAM) may guide EMB allowing to draw myocardial samples from abnormal voltage, areas of the ventricular wall, thus reducing sampling error and increasing the sensitivity of EMB. The systematic association of EAM with EMB represents a crucial approach to characterize the pathological substrate of electroanatomic abnormalities and VA and to further clarify the arrhythmogenic mechanisms of acquired and also inherited arrhythmic disorders.