Myocardial Fibrosis Assessment by LGE Is a Powerful Predictor of Ventricular Tachyarrhythmias in Ischemic and Nonischemic LV Dysfunction: A Meta-Analysis.

OBJECTIVES: The authors performed a meta-analysis to evaluate the predictive value of late gadolinium enhancement (LGE) cardiac magnetic resonance for ventricular tachyarrhythmia in ischemic cardiomyopathy (ICM) and nonischemic cardiomyopathy (NICM) patients with ventricular dysfunction.

BACKGROUND: The use of LGE to detect myocardial fibrosis and its related arrhythmic substrate is well established. Several recent studies have described the predictive value of LGE for ventricular tachyarrhythmias; however, their validity is limited by small sample size and low number of events.

METHODS: MEDLINE and the Cochrane Library electronic databases were systematically searched to identify studies that applied LGE in ICM and NICM patients with ventricular dysfunction and reported arrhythmic clinical outcomes (sudden death, aborted sudden death, ventricular tachycardia, ventricular fibrillation, and appropriate implantable cardioverter-defibrillator [ICD] therapy, including antitachycardia pacing). A meta-analysis was performed to determine pooled odds ratios (ORs) for these arrhythmic events.

RESULTS: Nineteen studies that evaluated 2,850 patients with 423 arrhythmic events over a mean/median follow-up of 2.8 years were identified. The composite arrhythmic endpoint was reached in 23.9% of patients with a positive LGE test (annualized event rate of 8.6%) versus 4.9% of patients with a negative LGE test (annualized event rate of 1.7%; p < 0.0001). LGE correlated with arrhythmic events in the different patient groups. In the overall population, the pooled OR was 5.62 (95% confidence interval [CI]: 4.20 to 7.51), with no significant differences between ICM and NICM patients. In a subgroup of 11 studies (1,178 patients) with mean ejection fraction (EF) ≤30%, the pooled OR for the arrhythmic events increased to 9.56 (95% CI: 5.63 to 16.23), with a negative likelihood ratio of 0.13 (95% CI: 0.06 to 0.30).

CONCLUSIONS: LGE is a powerful predictor of ventricular arrhythmic risk in patients with ventricular dysfunction, irrespective of ICM and NICM etiology. The prognostic power of LGE is particularly strong in patients with severely depressed EF, which suggests its potential to improve patient selection for ICD implantation.