CMR-Guided Lead Placement for Cardiac Resynchronization Therapy in a Patient with Congenitally Corrected Transposition of the Great Arteries (QF_TH_036)

Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart defect characterized by the atria and ventricles being connected in a reversed anatomical relationship. This condition often results in conduction system abnormalities, leading to a need for permanent pacemaker implantation. However, continuous ventricular pacing in ccTGA patients can induce ventricular dyssynchrony, potentially causing further systemic ventricular dysfunction and heart failure. In such cases, an upgrade to cardiac resynchronization therapy (CRT) becomes necessary to preserve cardiac function. However, due to the unique and complex anatomy of ccTGA, determining the optimal lead placement for CRT is challenging and requires a tailored approach.

Diagnostic Techniques and Their Most Important Findings:

Advanced imaging modalities such cardiac magnetic resonance (CMR) imaging, play a pivotal role in the pre-procedural planning of CRT in ccTGA patients. CMR allows for detailed assessment of cardiac function, scar tissue, and venous anatomy, which are critical in determining the optimal lead placement site. Feature tracking strain analysis on CMR, in particular, provides a robust method for identifying the myocardial region exhibiting the latest mechanical activation, essential for effective CRT. By visualizing mechanical activation patterns and scar tissue distribution using bulls-eye plots, clinicians can accurately target the ideal pacing site, avoiding areas of scar that would otherwise lead to suboptimal CRT response.  During the implantation procedure, real-time visualization of the target area can be achieved through the co-registration of the predefined target area onto the fluoroscopy images as facilitated by the CARTBox-Suite platform (CARTTech B.V., Utrecht, The Netherlands). The visualization of the target for lead deployment may enhance the likelihood of optimal pacing, as operators endeavor to position the ventricular lead as close as possible to the target area in a patient-specific manner.

Learning Points from this Case:

< ![if !supportLists] >-          < ![endif] >This case highlights the importance of a personalized, image-guided approach to CRT lead placement in patients with ccTGA. CMR imaging emerges as a key tool, offering precise localization of the optimal pacing site through detailed analysis of myocardial mechanics and scar tissue.

< ![if !supportLists] >-          < ![endif] >The integration of imaging data into procedural planning, along with real-time visualization during implantation, enhances the likelihood of successful lead placement, ultimately improving clinical outcomes.

< ![if !supportLists] >-          < ![endif] >This case underscores the necessity of personalized CRT strategies in ccTGA patients and the need for further research to fully elucidate the long-term benefits of imaging-guided lead placement in this unique patient population.