CMR-Based Risk Stratification of Sudden Cardiac Death and Use of Implantable Cardioverter–Defibrillator in Non-Ischemic Cardiomyopathy

Abstract

Non-ischemic cardiomyopathy (NICM) is one of the most important entities for arrhythmias and sudden cardiac death (SCD). Previous studies suggest a lower benefit of implantable cardioverter–defibrillator (ICD) therapy in patients with NICM as compared to ischemic cardiomyopathy (ICM). Nevertheless, current guidelines do not differentiate between the two subgroups in recommending ICD implantation. Hence, risk stratification is required to determine the subgroup of patients with NICM who will likely benefit from ICD therapy. Various predictors have been proposed, among others genetic mutations, left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic volume (LVEDD), and T-wave alternans (TWA). In addition to these parameters, cardiovascular magnetic resonance imaging (CMR) has the potential to further improve risk stratification. CMR allows the comprehensive analysis of cardiac function and myocardial tissue composition. A range of CMR parameters have been associated with SCD. Applicable examples include late gadolinium enhancement (LGE), T1 relaxation times, and myocardial strain. This review evaluates the epidemiological aspects of SCD in NICM, the role of CMR for risk stratification, and resulting indications for ICD implantation.

Implantable cardioverter‐defibrillator implantation in non‐ischaemic cardiomyopathy: towards individualized risk stratification

“…LGE represents areas of replacement fibrosis that provide substrate for ventricular re‐entrant tachyarrhythmia 8 . Interestingly, Di Marco and colleagues report that, when ICD therapies were excluded from their primary endpoint, the risk of adverse events was significantly greater in those with epicardial or transmural LGE compared to patients with midwall LGE 2 . An association between the location and pattern of LGE has been reported previously 6 .…”

“…Indeed, several predictors of SCD have been proposed, including high‐risk genotypes, electrical markers of risk such as T‐wave alternans and other measures of myocardial function, such as ventricular strain 2,3 . Additionally, a number of tissue characterization variables derived from cardiovascular magnetic resonance (CMR) imaging have been associated with an adverse prognosis including late gadolinium enhancement (LGE), T1 relaxation times and extracellular volume 2,3 …”

Association of late gadolinium enhancement in cardiac magnetic resonance with mortality, ventricular arrhythmias, and heart failure in patients with nonischemic cardiomyopathy: A systematic review and meta-analysis

“…LGE extent can be interpreted in various ways, including summation of segments with hyperenhancement, percentage of involved myocardium, or absolute weight of enhanced myocardium. 29 Interpretation is further complicated, as different LGE quantification techniques have been shown to cause wide variations in results in a single patient. 30 Perhaps it is because of these reasons that there is no current consensus on what extent of LGE is predictive of clinical events.…”

Analysis of susceptibility genes and myocardial infarction risk correlation of ischemic cardiomyopathy based on bioinformatics

“…As type of end-stage coronary atherosclerosis, in ICM, long-term imbalance between oxygen supply and demand leads to myocardial cell apoptosis and necrosis, cardiac fibrosis, and scar tissue formation, resulting in poor prognosis. For a prolonged period, ICM has lacked effective treatment because the necrosis of myocardial cells is an irreversible pathological process (12)(13)(14)(15). Although heart transplantation can replace the damaged heart, it is not widely carried out due to the limitations of donor availability and immune rejection (16).…”