Imaging phenotypes and substrates in ventricular tachycardia

Area of Science:

• Cardiology
• Medical Imaging
• Electrophysiology

Background:

• Ventricular tachycardia (VT) presents a significant clinical challenge due to heterogeneous myocardial substrates.
• Current assessment methods, focusing solely on scar burden, inadequately describe the complex arrhythmogenic substrate.
• Imaging modalities are crucial for identifying structural heart disease and guiding VT ablation strategies.

Purpose of the Study:

• To review ventricular tachycardia (VT) through the lens of imaging phenotypes and substrate characteristics, moving beyond scar burden alone.
• To summarize how advanced imaging can delineate substrate location, depth, tissue composition, and spatial distribution.
• To discuss the therapeutic implications of an imaging-based substrate framework for VT management.

Main Methods:

• Review of current literature on cardiac imaging in ventricular tachycardia (VT).
• Analysis of distinct imaging findings reflecting specific myocardial phenotypes (e.g., ischemic scar, nonischemic fibrosis, inflammatory injury, fibrofatty remodeling).
• Synthesis of how imaging data informs understanding of arrhythmogenic substrate and guides therapeutic decisions.

Main Results:

• Distinct imaging phenotypes represent different arrhythmogenic substrates with varying implications for VT mechanism and treatment.
• Imaging enables detailed characterization of substrate properties, including location, depth, tissue composition, and spatial distribution.
• An imaging-based substrate framework offers improved understanding of the arrhythmic ventricle and guides treatment planning, effect interpretation, and recurrence assessment.

Conclusions:

• Ventricular tachycardia (VT) substrate assessment requires a nuanced approach beyond scar burden, incorporating detailed imaging phenotypes.
• Advanced cardiac imaging is pivotal for comprehensive substrate characterization, enhancing the understanding and management of VT.
• Future directions involve refining imaging techniques and integrating substrate information for personalized VT ablation strategies.