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Mean entropy predicts implantable cardioverter-defibrillator therapy using cardiac magnetic resonance texture analysis of scar heterogeneity

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Pages (from-to)1242-1250
Number of pages9
JournalHeart Rhythm
Issue number8
Early online date5 Mar 2019
E-pub ahead of print5 Mar 2019
Published1 Aug 2019

King's Authors


BACKGROUND: Risk stratification of ventricular arrhythmia (VA) remains complex in both ischemic and non-ischemic populations.

OBJECTIVE: To determine whether scar heterogeneity, quantified by mean entropy, predicts appropriate ICD therapy. We hypothesize that higher mean entropy calculated from cardiac magnetic resonance texture analysis (CMR-TA) will predict appropriate ICD therapy.

METHODS: Consecutive patients underwent CMR imaging prior to ICD implantation. Short axis left ventricular scar was manually segmented. CMR-TA was performed using a Laplacian filter to extract and augment image features to create a scar texture, from which histogram analysis of pixel intensity was used to calculate mean entropy. The primary endpoint was appropriate ICD therapy.

RESULTS: 114 patients underwent CMR-TA (ICM n=70, NICM n=44) with median follow-up of 955 [IQR 691-1185] days. Mean entropy was significantly higher in the ICM group (5.7±0.7 vs. 5.5±0.7, P=0.045). Overall, 33 patients received appropriate ICD therapy. Using optimized cut-offs from ROC curves, Kaplan-Meier survival analysis demonstrated time until first appropriate therapy was significantly shorter in the high mean entropy group (P=0.003). Multivariable analysis showed mean entropy was the sole predictor of appropriate ICD therapy (HR 1.882, 95% CI 1.083-3.271, P=0.025). In the ICM group, mean entropy remained an independent predictor of appropriate ICD therapy whereas in the NICM group, T1-native was the sole predictor.

CONCLUSION: Scar heterogeneity, quantified by mean entropy using CMR-TA, was an independent predictor of appropriate ICD therapy in the mixed cardiomyopathy cohort and ICM-only group, suggesting a potential role for CMR-TA in predicting VA and risk-stratifying patients for ICD implantation.

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