VA or SCA can be an initial manifestation of isch- emic heart disease, cardiomyopathic processes, or myocarditis. Cardiac CT and cardiac MRI allow for evaluation of structural heart disease and assess- ment of LV and RV function including quantification of LVEF, LV mass and volume, valvular structure and coronary anatomy including anomalous coronary origins. Cardiac MRI can be useful in the evaluation for myocardial scar and infiltrative processes evi- dent as late gadolinium enhancement.S4.2.4-5 S4.2.4-9 Cardiac MRI also provides high-quality assessment of LV and RV function, size, and degree of fibrosis and is particularly useful in arrhythmogenic right ventricular cardiomyopathy and HCM. Recommendation for Biomarkers Referenced studies that support the recommendation are summarized in Online Data Supplement 7. COR LOE Recommendation IIa B-NR In patients with structural heart disease, measurement of natriuretic peptides (BNP or N-terminal pro-BNP) can be useful by adding prognostic information to standard risk factors for predicting SCD or SCA.S4.2.5-1 S4.2.5-4 Recommendation-Specific Supportive Text 1. Elevated levels of natriuretic peptides B-type natri- uretic peptide (BNP) or N-terminal pro-BNP are associated with increased risk of SCA and appro- priate ICD therapies, even after adjustment of LVEF and other risk factors.S4.2.5-1 S4.2.5-4 These biomarkers are also predictive of nonsudden cardiovascular mortality and thus are not specific to SCD risk alone. 