Cardiac imaging to predict malignant arrhythmias in non-ischemic cardiomyopathy

Abstract

Sudden cardiac death (SCD) remains a major contributor to cardiovascular disease mortality, accounting for approximately half of all related deaths. Non-ischemic cardiomyopathy (NICM) presents itself as a common yet challenging cardiac condition. High-risk patients could potentially benefit from implantable cardioverter defibrillators (ICD). However, the limited capacity to accurately identify these individuals results in unnecessary procedures for some and overlooked preventative measures for others, leading to potentially avoidable mortality. The conventional approach to assessing the risk of SCD has primarily involved evaluating the ejection fraction (EF) via echocardiography. However, advanced cardiac imaging techniques, such as cardiac magnetic resonance imaging (CMR), computed tomography (CT), positron emission tomography (PET), and single-photon emission computerised tomography (SPECT) have emerged as promising non-invasive methods for VA and SCD risk assessment. These imaging modalities offer valuable insights into the structural and functional abnormalities that predispose individuals to sudden cardiac death. As a result, these advanced imaging methods have the potential to enhance risk stratification and improve patient outcomes by identifying individuals at high risk of SCD who may benefit from early interventions. This review aims to fill a critical gap in current literature by identifying which imaging features are most strongly associated with malignant arrhythmias in NICM, thus moving beyond traditional risk markers. Each modality provides unique insights into structural, functional, or metabolic changes that may indicate arrhythmogenic potential in NICM. Systematically assessing each imaging method's strengths contributes to a deeper understanding of their individual roles in risk stratification.