Left Ventricular Late Gadolinium Enhancement for Arrhythmic Risk Prediction in ARVC
Can MRI-Detected Heart Scarring Improve Risk Prediction in ARVC?
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart condition that can lead to dangerous abnormal heart rhythms and, in some cases, sudden cardiac death. To prevent this, some patients may receive an implantable cardioverter-defibrillator (ICD), a device that can detect and stop life-threatening arrhythmias. However, deciding which patients truly benefit from an ICD is difficult because ARVC can vary widely from person to person. To help with this decision, doctors can use a tool called the ARVC risk calculator, developed in 2019. It estimates a patient’s risk of serious arrhythmias using several common clinical factors, such as age, sex, fainting episodes, changes on the electrocardiogram (ECG), short runs of abnormal heart rhythms, the number of extra heartbeats on monitoring, and how well the right ventricle of the heart pumps. This calculator is widely used and performs well in many patients, especially those with classic forms of ARVC. However, it does not directly include detailed information about structural changes in the left side of the heart.
In other types of heart disease, scarring in the left ventricle—the heart’s main pumping chamber—has been shown to increase the risk of dangerous arrhythmias. This scarring can be seen on cardiac MRI (Magnetic Resonance Imaging, a medical test that takes highly detailed, 3D pictures of the heart) as so-called late gadolinium enhancement (LGE). Certain patterns of scarring, particularly those affecting the outer layer of the heart muscle or involving larger areas, have been considered especially high risk in other heart conditions. Because this type of left-sided scarring is not included in the ARVC risk calculator, smaller earlier studies explored whether LGE could improve risk prediction in ARVC. Although those studies suggested a possible role, they were too small to clearly determine whether adding MRI scarring information would meaningfully improve the existing calculator. Since a substantial proportion of people with ARVC show signs of left-ventricle involvement on MRI, understanding whether this information adds value is important.
To answer this question, researchers combined data from 385 patients with a definite diagnosis of ARVC treated at 17 hospitals across 11 countries in Europe and North America. This is the largest study to date examining this issue in patients with ARVC who had MRI scans. All participants had never experienced a sustained dangerous heart rhythm before entering the study and had undergone a cardiac MRI around the time of diagnosis. About one in three patients showed scarring in the left ventricle on their MRI, and about one in four had a scarring pattern considered higher risk. The patients were followed for a little over three years on average to see who developed serious arrhythmias. Overall, about one in six patients experienced such an event. Most of these events were treated by ICDs that successfully stopped the dangerous rhythm, while only a small number experienced cardiac arrest, meaning that the heart stops beating.
At first glance, patients with left-ventricular scarring were more likely to develop dangerous heart rhythms. In fact, those with scarring had roughly an 80 percent higher risk of a serious arrhythmia compared with those without scarring. However, when researchers adjusted for each patient’s risk as estimated by the established ARVC risk calculator, the presence or pattern of scarring no longer added meaningful information. Even when focusing specifically on the higher-risk scarring patterns, the results were the same. Adding MRI scarring to the risk calculator did not improve its ability to predict which patients would go on to develop dangerous arrhythmias. The researchers also repeated their analysis after excluding certain genetic forms of ARVC that more strongly affect the left side of the heart, and the findings did not change.
When the researchers examined why this happened, they found that left-ventricular scarring was closely linked to several of the individual warning signs already included in the ARVC risk calculator. Patients with scarring were more likely to have short bursts of abnormal heart rhythms, a higher number of extra heartbeats on monitoring, more pronounced ECG changes, and weaker pumping function of the right side of the heart. In other words, the scarring often appeared alongside other signs of more advanced or active disease. Because the calculator already incorporates these rhythm abnormalities and heart function measurements, it was likely already capturing much of the risk that the scarring represents. Once these overlapping factors were taken into account, the additional effect of the MRI finding essentially disappeared.
Overall, this large international study shows that although left-ventricular scarring on MRI is common in ARVC and is associated with a higher risk of dangerous arrhythmias, it does not independently improve the performance of the current ARVC risk calculator in patients with a definite diagnosis who have not previously experienced a major arrhythmia. These results support continued use of the established risk calculator to guide decisions about ICD implantation, regardless of whether left-sided scarring is present on MRI.
De Marco C, Asatryan B, te Riele ASJM, Di Marco A, Gasperetti A, Delinière A, Roberts JD, Jensen HK, Davies B, Krahn AD, Tadros R, Svensson A, Castelletti S, Crotti L, Platonov PG, Borowiec K, Biernacka EK, Arbelo E, David LP, Saguner AM, Healey JS, Brunckhorst C, Cappelletto C, Stolfo D, Merlo M, Rootwelt-Norberg C, Haugaa KH, Duru F, van Tintelen JP, Velthuis BK, Calkins H, Zimmerman SL, James CA, Bosman LP, Cadrin-Tourigny J.
Left Ventricular Late Gadolinium Enhancement for Arrhythmic Risk Prediction in ARVC. Circ Arrhythm Electrophysiol. 2026;19:e014265. doi: 10.1161/CIRCEP.125.014265.
Prepared by Laurens Bosman and Ruth Biller