Anatomic complexities of the human right ventricle: Considerations for clinical practice in the electrophysiology laboratory

Human cardiac ventricular anatomy is extremely complex and highly variable. Clinical electrophysiological assessments of ventricular chambers are often necessary for treating ventricular arrhythmias. Electrophysiologists performing ablations often rely on fluoroscopy and electroanatomic maps to navigate catheters through complex functional anatomies. However, limited imaging and mapping system resolution may not provide sufficient detail relative to underlying anatomic structures and conduction pathways. We aimed to illustrate the wide range of anatomic structures within the right ventricle and discuss how they may create procedural challenges. The Visible Heart Laboratories have built an anatomic database of >850 human hearts, including direct visualizations from reanimated and preserved hearts. We present detailed images of the complexity and variation of anatomic areas important to therapies applied to the right ventricle, including (1) the subvalvular apparatus (papillary complexes and chordae variations), (2) the moderator band and other conduction system features, (3) degrees of trabeculation and its contributions to variations in myocardial wall thickness, and (4) distributions of epicardial fat. Furthermore, we discuss the implications of these anatomies on approaches to electroanatomic mapping and ablation. This comprehensive review with novel images of complex anatomic features in normal and diseased hearts provides insights to aid clinicians in their electrophysiology practice.