Conclusion:
By pooling the adjusted HR for minimize the influence of clinical differences between CRT-P and CRT-D recipients, our work demonstrates an association of additional ICD and a lower all-cause mortality, especially in patients with ICM. CRT-D did not manifest a survival benefits in patients with older age (≥75 years), NICM, or using for primary prevention, which provides an implication in risk stratification of patients. RCTs are still needed to explore the real effect of additional ICD in mortality.