Single-photon emission computed tomographic-multidetector computed tomographic fusion image integration: a potential aid to left ventricular substrate ablation

Twenty-five years of research in cardiac imaging in electrophysiology procedures for atrial and ventricular arrhythmias

Catheter ablation is nowadays considered the treatment of choice for numerous cardiac arrhythmias in different clinical scenarios. Fluoroscopy has traditionally been the primary imaging modality for catheter ablation, providing real-time visualization of catheter navigation. However, its limitations, such as inadequate soft tissue visualization and exposure to ionizing radiation, have prompted the integration of alternative imaging modalities. Over the years, advancements in imaging techniques have played a pivotal role in enhancing the safety, efficacy, and efficiency of catheter ablation procedures. This manuscript aims to explore the utility of imaging, including electroanatomical mapping, cardiac computed tomography, echocardiography, cardiac magnetic resonance, and nuclear cardiology exams, in helping electrophysiology procedures. These techniques enable accurate anatomical guidance, identification of critical structures and substrates, and real-time monitoring of complications, ultimately enhancing procedural safety and success rates. Incorporating advanced imaging technologies into routine clinical practice has the potential to further improve clinical outcomes of catheter ablation procedures and pave the way for more personalized and precise ablation therapies in the future.

Role of Imaging in the Management of Ventricular Arrhythmias

The management of ventricular arrhythmias (VA) has evolved over time to an advanced discipline, incorporating many technologies in the diagnosis and treatment of the myriad types of VA. The first application of imaging is in the assessment for structural heart disease, as this has the greatest impact on prognosis. Advanced imaging has its greatest utility in the planning and execution of ablation for VA. The following review outlines the application of different imaging modalities, such as ultrasonography, magnetic resonance imaging, computed tomography, and positron emission tomography, for the treatment of VA.

Nuclear image-guided left ventricular pacing lead navigation feasibility of a new technique

PURPOSE

Current techniques for left ventricular (LV) lead implantation in patients with ischemic cardiomyopathy (ICM) typically underutilize information which is important for optimal lead location, including LV mechanical activation pattern and scar location. We sought to develop a technique in which this information, contained in single-photon emission computed tomographic (SPECT) images, could be integrated as to guide the electrophysiologist during the implantation procedure.

METHODS

Five ICM patients underwent SPECT as well as multidetector cardiac computed tomographic (MDCT) imaging prior to the LV lead implantation procedure. Images were merged to create a "fusion" image, in which the SPECT data were projected onto the anatomically accurate MDCT epicardial surface. The fusion image was registered to the operative field using the coronary veins, apparent on the MDCT image, as a fiducial system. After registration, LV lead implantation was guided by the fusion image using a commercial catheter navigation system.

RESULTS

Successful guidance was achieved in each patient, with minimal disturbance to standard workflow. Leads were implanted in late-activating, unscarred regions according to the fusion image, with locations corroborated by fluoroscopic and electrographic features. In regions where leads were contiguous to the phrenic nerve shown on the fusion image, pacing consistently demonstrated diaphragmatic stimulation.

CONCLUSIONS

In this technical report, the description and feasibility of a new technique for SPECT image-guided LV pacing lead navigation is demonstrated. Prospective study will be required to confirm image precision and registration/navigation accuracy, as well as to demonstrate value relative to standard implantation techniques.