Provided herein are methods that include (i) determining a level of soluble ST2 in a biological sample from a subject, (i) comparing the level of soluble ST2 in the biological sample to a reference level of soluble ST2 (e.g., a level of soluble ST2 in the subject at an earlier time point), and (iii) selecting, implanting, replacing, or reprogramming an implanted cardiac device, e.g., an ICD, CRT, or CRT-D device, for a subject having an elevated level of soluble ST2 in the biological sample compared to the reference level of soluble ST2, or selecting a subject for participation in, or stratifying a subject participating in, a clinical study of a treatment for reducing the risk of a ventricular tachyarrhythmia (VTA) event. Also provided are methods for evaluating the risk of a VTA event in a subject. Also provided are kits for performing any of these methods.