AUTHOR: Jordan Rance

Risk stratification for primary prevention implantable cardioverter-defibrillator (ICD) placement in patients with cardiac sarcoidosis remains a clinical challenge, partly due to inconsistencies in diagnostic criteria and the variable course of the disease. A new study published in the European Heart Journal suggests that cardiovascular magnetic resonance (CMR) phenotyping has greater discriminative accuracy for predicting long-term ventricular arrhythmic outcomes compared to current societal recommendations, potentially refining patient selection for ICD therapy.¹

This large, multicentre study retrospectively analysed data from 1,514 patients with histology-supported sarcoidosis. All participants had undergone CMR for suspected cardiac involvement and were ineligible for a secondary prevention ICD at baseline. The researchers compared the predictive accuracy of two risk stratification methods: eligibility for an ICD based on societal recommendations, such as those from the Heart Rhythm Society (HRS),² and a risk profile determined by CMR phenotyping. The primary composite outcome was fatal or life-threatening ventricular arrhythmias, including sudden cardiac death, sustained ventricular tachycardia, or appropriate ICD therapy.

During a median follow-up of 4.5 years (maximum 10 years), 84 patients (5.5%) experienced the primary outcome. Patients identified as having a high-risk CMR phenotype had a significantly higher cumulative incidence of the outcome at 5 years (24.0%) and 10 years (35.0%). In contrast, those with a low-risk CMR phenotype had a much lower incidence of 0.7% at 5 years and 2.6% at 10 years. The study found that CMR phenotyping demonstrated superior discriminative accuracy, with an area under the curve (AUC) of 0.861 for 5-year outcomes and 0.776 for 10-year outcomes. Furthermore, after multivariable adjustment, CMR phenotyping was associated with the highest subdistribution hazard ratio for the study outcome (19.8).¹

The findings indicate that in patients with suspected cardiac sarcoidosis, CMR phenotyping is a more effective tool for identifying individuals at high risk for life-threatening ventricular arrhythmias than current societal guidelines. This suggests that a CMR-based risk stratification approach could improve the selection of candidates who would benefit most from primary prevention ICDs, while potentially avoiding unnecessary device implantation in low-risk individuals. The study authors concluded that CMR phenotyping "showed greater discriminative accuracy than societal recommendations for predicting fatal or life-threatening ventricular arrhythmias, suggesting that it may be more effective at identifying candidates for primary prevention ICDs."¹

References

1. Mathijssen H, Bawaskar PH, Rochlani Y, et al. Prediction of ventricular arrhythmic outcomes in suspected cardiac sarcoidosis: a comparison of cardiovascular magnetic resonance phenotyping vs. societal recommendations for implantable cardioverter-defibrillator placement. Eur Heart J. 2025;46(36):3583-3596. https://doi.org/10.1093/eurheartj/ehaf338

2. Birnie DH, Sauer WH, Bogun F, et al. HRS expert consensus statement on the diagnosis and management of arrhythmias associated with cardiac sarcoidosis. Heart Rhythm. 2014;11(7):1305-1323. https://doi.org/10.1016/j.hrthm.2014.03.043

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