Life-Threatening Ventricular Arrhythmias: Current Role of Imaging in Diagnosis and Risk Assessment

Area of Science:

• Cardiology
• Medical Imaging
• Biomarkers

Background:

• Sudden cardiac arrest (SCA) remains a leading cause of cardiovascular death.
• Current risk stratification, primarily using left ventricular ejection fraction (LVEF), has limited accuracy in predicting lethal ventricular arrhythmias.
• LVEF is insufficient for optimal patient selection for primary prevention implantable cardioverter-defibrillators (ICDs).

Purpose of the Study:

• To review advanced imaging modalities for identifying patients at high risk of lethal ventricular arrhythmias.
• To explore how these imaging techniques can refine patient selection for primary prevention ICDs beyond LVEF.
• To discuss emerging risk prediction models incorporating imaging and biomarkers.

Main Methods:

• Review of current literature on advanced cardiac imaging techniques.
• Focus on Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT) for myocardial sympathetic innervation.
• Emphasis on gadolinium-enhanced cardiac magnetic resonance (CMR) for myocardial infarct characterization.

Main Results:

• Advanced imaging modalities like PET, SPECT, and CMR offer potential to improve risk stratification for sudden cardiac death.
• These techniques may provide more precise information on myocardial viability and sympathetic innervation compared to LVEF alone.
• Emerging risk prediction models integrating quantitative imaging and biomarkers show promise.

Conclusions:

• Advanced imaging techniques are crucial for refining risk assessment in patients with left ventricular dysfunction.
• Improved risk prediction can lead to better patient selection for primary prevention ICDs, potentially reducing sudden cardiac death.
• Further prospective studies are needed to validate these imaging-based risk prediction models.