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Improving Risk Stratification in Dilated Cardiomyopathy
Quick Takes
- Late gadolinium enhancement (LGE) is a strong, consistent, and specific predictor of ventricular arrhythmias and sudden death in dilated cardiomyopathy (DCM) across the entire LVEF spectrum.
- A clinical algorithm that integrates LVEF and LGE, as assessed by CMR imaging, may have important clinical implications, as it could provide a more efficient strategy for targeting primary prevention ICDs.
- There is a need for randomized trials to help identify patients with nonischemic DCM with LGE who may benefit from implantation of ICDs and to assess outcomes.
Study Questions:
What is the impact of late gadolinium enhancement (LGE) on ventricular arrhythmias (VA) and sudden death across a range of left ventricular ejection fraction (LVEF) strata, and can an improved algorithm for the risk stratification of VA and sudden death in patients with dilated cardiomyopathy (DCM) be developed?
Methods:
The investigators conducted a retrospective cohort study of consecutive patients with DCM who underwent cardiac magnetic resonance (CMR) with LGE at two tertiary referral centers. The combined arrhythmic endpoint included appropriate implantable cardioverter-defibrillator (ICD) therapies, sustained ventricular tachycardia, resuscitated cardiac arrest, and sudden death. The comparison between risk stratification models was performed by comparing the area under the receiver-operating characteristic (AUC) curves using the algorithm proposed by DeLong, et al. The added value of the new risk stratification strategy was also calculated by using the relative Integrated Discrimination Improvement index.
Results:
In 1,165 patients with median follow-up of 36 months, LGE was an independent and strong predictor of the arrhythmic endpoint (hazard ratio [HR], 9.9; p < 0.001). This association was consistent across all strata of LVEF. Epicardial LGE, transmural LGE, and combined septal and free-wall LGE were all associated with heightened risk. A simple algorithm combining LGE and three LVEF strata (≤20%, 21%-35%, >35%) was significantly superior to LVEF with the 35% cut-off (Harrell’s C statistic 0.8 vs. 0.69, AUC 0.82 vs. 0.7, p < 0.001) and reclassified the arrhythmic risk of 34% of DCM patients: LGE-negative patients with LVEF 21%-35% had low risk (annual event rate 0.7%), while those with high risk LGE distributions and LVEF >35% had significantly higher risk (annual event rate 3%, p = 0.007).
Conclusions:
The authors concluded that in DCM, LGE was a significant, consistent, and strong predictor of VA or sudden death.
Perspective:
This cohort study reports that LGE is a strong, consistent, and specific predictor of VA and sudden death in DCM across the entire LVEF spectrum. Furthermore, the predictive power of LGE increases with slighter LV impairment and is greatest among patients not currently covered by primary prevention ICD guidelines. A clinical algorithm that integrates LVEF and LGE, as assessed by CMR imaging, may have important clinical implications, as it could provide a more efficient strategy for targeting primary prevention ICDs. However, given the retrospective nature of the current analysis, there is a need for randomized trials to help identify patients with nonischemic DCM with LGE who may benefit from implantation of ICDs and to assess outcomes.
Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Magnetic Resonance Imaging
Keywords: Arrhythmias, Cardiac, Cardiomyopathy, Dilated, Contrast Media, Death, Sudden, Defibrillators, Implantable, Diagnostic Imaging, Gadolinium, Heart Arrest, Heart Failure, Magnetic Resonance Imaging, Primary Prevention, Risk Assessment, Stroke Volume, Tachycardia, Ventricular, Ventricular Function, Left
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