Myocardial Scar Characterization and Future Ventricular Arrhythmia in Patients With Ischemic Cardiomyopathy and an Implantable Cardioverter-Defibrillator

Abstract

Background: Implantable cardioverter-defibrillator (ICD) therapy is associated with several deleterious effects, which can be reduced by antiarrhythmic drugs or catheter ablation. However, it is largely unknown which patients might benefit from these therapies. Therefore, this study aimed to investigate whether myocardial scar characterization improves risk stratification for ventricular arrhythmia (VA) occurrence in patients with ischemic cardiomyopathy and an ICD.Methods: In this study, 82 patients with ischemic cardiomyopathy who received an ICD were enrolled retrospectively. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) images were analyzed using an investigational software tool to obtain quantitative data regarding the total scar, core, and border zone (BZ). Data regarding the QRS complex was obtained from electrocardiography (ECG). The primary endpoint was appropriate ICD therapy.Results: During a median follow-up duration of 3.98 years [interquartile range (IQR) 2.89–5.14 years], appropriate therapy occurred in 24 (29.3%) patients. Patients with appropriate ICD therapy had a significantly larger total scar mass [60.0 (IQR 41.2–73.4) vs. 43.3 (IQR 31.2–61.2) g; P = 0.009] and BZ mass [32.9 (IQR 26.9–42.4) vs. 24.5 (IQR 18.8–32.5) g; P = 0.001] than those without appropriate therapy. In multivariable Cox regression analyses, total scar mass [hazard ratio (HR) 1.02 [95% confidence interval (CI) 1.00–1.04]; P = 0.014] and BZ mass (HR 1.04 [95% CI 1.01–1.07]; P = 0.009) independently predicted appropriate ICD therapy. Core mass and the QRS complex, however, were not significantly associated with the primary endpoint.Conclusion: LGE-CMR-based, but not ECG-based myocardial scar characterization improves risk stratification for VA occurrence in patients with ischemic cardiomyopathy who received an ICD.

Correlation between Pre-Operative Myocardial Fibrosis and Early Post CABG Dysrhythmia

“…Noordman et al [16] shown that in individuals who have survived a myocardial infarction, the extent of the scar's "border zone" area serves as an indicator for predicting ventricular arrhythmic episodes and long-term mortality. study.…”

Prognostic Value of Cardiac‐MRI Scar Heterogeneity Combined With Left Ventricular Strain in Patients With Myocardial Infarction

“…Thus, more accurate risk assessment instruments are urgently needed. A study of patients after MI who received ICDs showed BZ mass and total fibrosis mass on cardiac MRI independently predicted appropriate ICD therapy 10 . BZ is thought to be the arrhythmic substrate within the myocardium for ICM 11 .…”

“…After MI BZ entropy as the predictor for appropriate ICD therapy and long-term mortality in patients after MI was recognized by a large quantity of prospective trials, systematic review, and meta-analysis. 10,18,19 In addition, cardiac MRI-derived scar quantitation was recommended as a tool to guide risk stratification and cardioprotective treatment for improving clinical outcomes in post-MI patients by American College of Cardiology Foundation. 20 Studies have focused on scar extent, but few have evaluated its heterogeneity.…”

“…A study of patients after MI who received ICDs showed BZ mass and total fibrosis mass on cardiac MRI independently predicted appropriate ICD therapy. 10 BZ is thought to be the arrhythmic substrate within the myocardium for ICM. 11 Because cardiac MRI is recognized as the best tool to evaluate myocardial fibrosis and the parameters can be used to predict SCD, it has emerged as the modality of choice to assess BZ scar in patients after MI.…”

Editorial: Strategies to improve management of ventricular tachycardias

“…Non-invasive programmed stimulation to induce monomorphic VT via the ICD might be an attractive diagnostic tool to identify patients at high risk for future events (5) and even offer early treatment with antiarrhythmic drugs or VT ablation. Lastly, even among patients with current secondary prevention ICD indication, many will never develop recurrent arrhythmias and identification of a low-risk subgroup might prevent unnecessary ICD implantations with the inherent reduction in patients' quality of life and increase in health care expenditures (6). Also in this patient group, CMR may aid in identifying patients at low risk of recurrence (7).…”