This diagnostic image consists of two axial Multi-Detector Computed Tomography (MDCT) scans (A and B) focusing on the cardiac anatomy of the right atrium and its conduction system.

A 3D diagnostic anatomical reconstruction illustrating the Cardiac Conduction System (CCS) in a mammalian heart. The image is divided into three panels (A, B, C) showing varying levels of transparency of the myocardium. In Panel A, the CCS is isolated in yellow, highlighting major components: the Sinoatrial Node (SAN), His Bundle (HB), Penetrating Bundle (PB), Right Bundle Branch (RBB), Left Bundle Branch (LBB), and the extensive Purkinje Network (PN). Panels B and C overlay the yellow conduction network onto the pink myocardial mass with decreasing transparency. Key anatomical regions labeled include the Right Atrium (RA), Left Atrium (LA), Right Ventricle (RV), Left Ventricle (LV), and the Interventricular Septum (IVS). The visual emphasizes the distribution and density of conduction fibers throughout the heart, specifically showing how the bundle branches descend along the IVS before arborizing into a dense meshwork (Purkinje fibers) within the ventricular walls to facilitate coordinated contraction.

This composite image presents four panels (a–d) of computerized cardiac simulations focusing on stratified heart wall models and electrophysiological properties. Panel (a) shows a 2-D stratified heart model with multi-colored concentric layers representing the endocardium-to-epicardium transition in the ventricular walls. Panel (b) illustrates a 2-D simulation of epicardium-to-endocardium repolarization, with a color gradient (green to dark blue) mapped to transmembrane potential across the myocardium. Panel (c) highlights two areas of myocardial ischemia, visualized through variations in blue and cyan shades. Panel (d) displays a cross-sectional view of a 3-D stratified model, further demonstrating the arc-shaped fiber orientation and wall layering. The models utilize cellular automata to represent different cardiac tissues, including the sinoatrial node (SAN), atrioventricular node (AVN), and the conduction system (bundle branches and Purkinje fibers). These simulations are designed for medical education and research into arrhythmia generation, ischemia effects, and the electrical heterogeneity of the heart walls, particularly the simulation of M cells and transmural action potential duration gradients.

This composite clinical image presents a multimodal evaluation of a permanent pacemaker system. Panel A is a posteroanterior (PA) chest radiograph showing the cardiac silhouette, lungs, and the pacemaker generator in the left infraclavicular region with leads traversing the venous system. Panel B is a lateral chest radiograph providing a profile view of the lead trajectory. Panel C is an axial computed tomography (CT) scan through the heart. In all three panels, red arrowheads highlight the distal tip of the right ventricular (RV) lead. The CT scan (C) specifically provides high-resolution anatomical localization, with labels for the right atrium (RA), right ventricle (RV), left ventricle (LV), and left atrium (LA). It demonstrates the RV lead implanted at the basal interventricular septum, visualized as a high-density, radiopaque structure. This series illustrates the use of multi-planar imaging to confirm lead positioning and evaluate potential cardiac device complications or anatomical placement relative to the interventricular septum.

This composite diagnostic image features a posterior-anterior (PA) chest radiograph (left) and a magnified lateral-oblique view (right) of a dual-chamber permanent pacemaker. The primary radiograph shows the pacemaker pulse generator (can) implanted in the left infraclavicular region, with two radiopaque leads traversing the subclavian vein into the right atrium and right ventricle. The magnified image highlights key markers used to identify MRI-conditional (MRI-safe) status. A long white arrow points to a specific radiopaque wavy line and alphanumeric code ('PVX') on the device header, mirrored by a schematic inlay for clarity. Short white arrows indicate similar wavy radiopaque markers located on the proximal portion of the leads. These visual identifiers are critical for clinicians to verify that the implanted Cardiac Rhythm Management (CRM) device is compatible with magnetic resonance imaging environments, a standard feature in modern pacing systems used for patients requiring ongoing serial MRI monitoring.

This diagnostic image is a postero-anterior (PA) chest radiograph demonstrating severe cardiomegaly and an implanted cardiac device. The cardiac silhouette is massively enlarged, exhibiting a cardiothoracic ratio (CTR) of approximately 70.6%, which is characteristic of advanced hypertrophic cardiomyopathy (HCM). A permanent dual-chamber pacemaker is visible in the left infraclavicular region (viewer's right). Two radiopaque leads originate from the generator; one lead terminates in the right atrium, and the second lead courses medially and inferiorly to terminate in the right ventricle. The lungs appear relatively clear, though the excessive cardiac volume significantly displaces the adjacent pulmonary structures. This radiograph serves as a clinical example of cardiac remodeling and secondary pacemaker implantation required for rhythm management in patients with complex cardiomyopathies and conduction system diseases, such as those associated with PRKAG2 mutations or Wolff-Parkinson-White syndrome.