Cardiac implantable electronic devices (CIEDs) are widely used to treat patients with heart failure, malignant arrhythmias, and other conditions. However, accurately identifying suitable candidates for CIED implantation remains a clinical challenge. Cardiovascular magnetic resonance imaging (CMR) provides a comprehensive assessment of cardiac structure, function, and tissue characteristics, facilitating evaluation of the myocardial substrate for arrhythmias. This study aims to evaluate the prognostic value of multiparametric CMR-derived imaging markers in CIED patients through preoperative CMR examinations. Imaging parameters of interest include structural-functional indices, myocardial strain, late gadolinium enhancement, entropy, and T1 and T2 mapping. Long-term clinical outcomes will be obtained from existing medical records and follow-up. The primary endpoint is sudden cardiac death (SCD) or SCD-equivalent events, defined as SCD, resuscitated cardiac arrest, sustained ventricular tachycardia or ventricular fibrillation, or appropriate ICD therapy. Secondary endpoints include all-cause mortality or heart failure rehospitalization. This study aims to elucidate the role of CMR in assessing CIED treatment indications and long-term risk stratification, thereby helping to optimize CIED implantation decisions.