What is already known?
1. Majority of heart failure (HF) guideline recommended medications were proved to reduce HF hospitalization and overall mortality.
2. ICD and CRTD primary prevention implant in symptomatic HF patients with low EF with narrow and wide LBBB, respectively, were sown to reduced overall mortality.
3. The impact of HF medication regarding ventricular arrhythmia is less robust.