Background <p>Patients experiencing end-stage heart failure are a particularly important population who carry with them a heavy disease burden. However, evidence related to palliative care for patients with end-stage heart failure remains scarce, particularly when it comes to the issue of palliative care consultation service (PCCS). This 4-year observational study aimed to evaluate the effects of PCCS on opioid use and aggressive treatment during end of life (EOL) among patients diagnosed with end-stage heart failure.</p> Methods <p>This observational study used the hospice palliative care database of a tertiary medical center in Taiwan. We enrolled all decedents who were diagnosed with end-stage heart failure from the period January 1, 2018 to December 31, 2021. PCCS prior to death was documented with the relationship between PCCS and opioid use and treatment aggressiveness during EOL then analyzed through use of multivariable logistic regression.</p> Results <p>A total of 120 patients were enrolled, which included 60 (50.0%) patients with end-stage heart failure who received PCCS prior to death. Compared with patients who did not receive PCCS, patients with PCCS during EOL were found to have had significantly more opioids use (odds ratio and 95% confidence interval: 3.192, 1.311–7.768) as well as a greater likelihood of their hospitalization extending for more than 14 days (odds ratio and 95% confidence interval: 4.454, 1.863–10.651) during EOL. Even though patients who received PCCS did not experience significantly different combined treatment aggressiveness during EOL, they received less CPR and had more DNR consent orders. Moreover, the promotion of PCCS increased disease awareness in both patients and their families.</p> Conclusion <p>PCCS in patients diagnosed with end-stage heart failure during EOL could significantly increase their opioid use and reduce some forms of aggressive treatments during EOL.</p>