Background: A limited number of studies have explored the association between rheumatoid arthritis (RA) and heart failure (HF) based on HF subtype (ischemic and non-ischemic) and RA serostatus. Objective: This study aimed to examine the association between RA and incident HF, considering serostatus (seropositive RA[SPRA], seronegative RA[SNRA]) and HF subtype. Methods: This retrospective cohort utilized nationwide population data from the National Health Insurance Service (NHIS) of Korea. The study analyzed 46,975 RA patients (33,424 SPRA, 13,551 SNRA) diagnosed in 2010–2017, along with 140,925 matched non-RA controls. Results: The RA patients had a higher risk of overall HF (adjusted hazard ratio (aHR) 1.97, 95% confidence interval (CI) 1.68–2.32), and risk was more prominent for ischemic HF (aHR 2.24, 95% CI 1.86–2.71) than non-ischemic HF (aHR 1.36, 95% CI 0.97–1.90). Compared with controls, the risk of overall HF was increased in both SPRA (aHR 2.13, 95% CI 1.78–2.55) and SNRA (aHR 1.59, 95% CI 1.19–2.11), with a non-significant trend toward a higher risk in SPRA than in SNRA (aHR 1.35, 95% CI 0.99–1.83). For non-ischemic HF, the risk was increased in SPRA (aHR 1.60, 95% CI 1.12–2.28) but not in SNRA (aHR 0.71, 95% CI 0.32–1.51); however, this finding was based on a small number of events. Conclusions: This study demonstrates that RA was significantly associated with an increased risk of overall and ischemic HF, with a non-significant trend toward an increased risk of non-ischemic HF. The increased risk of ischemic HF was observed in both SPRA and SNRA, whereas the difference in non-ischemic HF risk by serostatus should be interpreted with caution due to the small number of events.