• cardiac magnetic resonance
• myocardial infarction
• late gadolinium enhancement
• dispersion mapping

BACKGROUND: Myocardial fibrosis is a major pathophysiologic determinant of arrhythmic propensity in both ischemic cardiomyopathy (ICM) and non-ICM (NICM). Recently a novel LGE image analysis method, named LGE-dispersion mapping was proposed as a new tool to predict arrhythmogenic in Hypertrophic cardiomyopathy (HCM). Here, we proposed this method to predict arrhythmogenic in the context of stable coronary heart disease after myocardial infarction with LVEF >35%.
METHODS: CMR was performed in 220 consecutive patients who had clinical evidence of an earlier MI (> 90 days prior) and LV EF > 35%. A parametric map was generated from each LGE image. A score from 0 to 8 was assigned at every pixel of these maps, indicating the number of the surrounding pixels having different quality (nonenhancement, mild-enhancement, or hyperenhancement) from the central pixel. The Global Dispersion Score (GDS) was calculated as the average score of all the pixels of the images.
RESULTS: During a clinical follow-up of 682 days (324 – 1327), 14 patients had events ( death for all causes, cardiac death, resuscitated cardiac arrest, and the proper ICD shock or anti-tachycardia pacing). GDS emerged as the only independent predictor of hard events. The Kaplan-Meier analysis showed that patients with GDS>0.5 had worse prognosis than those with lower GDS (Logrank p < 0.0001).
CONCLUSIONS: GDS is a new quantitative marker for the evaluation of heterogeneity and dispersion in myocardial fibrosis in the context of various forms of heart disease. For patients with a history of myocardial infarction at LVEF> 35%, GDS has a predictive role in identifying patients at higher risk for major cardiac events