Despite numerous trials on revascularization in patients with heart failure (HF) and ischaemic left ventricular (LV) dysfunction, its role remains unsettled. Guideline-directed medical therapy (GDMT) for HF has shown benefits on outcomes. This multicentre study aims to compare long-term mortality between revascularization and GDMT in patients with ischaemic LV dysfunction following admission for HF. Between 2012 and 2023, 408 patients admitted for HF with a LV ejection fraction (LVEF) of 40% or less and documented coronary artery disease (CAD) were included. Patients were categorized into two groups based on their initial treatment decision: revascularization (percutaneous coronary intervention [PCI] or coronary artery bypass graft [CABG]) or GDMT. The primary outcome was rate of all-cause or cardiovascular mortality, and secondary outcomes included type of revascularization (PCI vs. CABG) and LV reverse remodelling. After a median 44.6-month follow-up, 100 patients (33%) died in the revascularization group, compared to 44 (43%) in the GDMT group. Multivariate analysis showed no significant benefit of revascularization on all-cause mortality (hazard ratio [HR] 0.81, 95% confidence interval [CI] 0.48-1.39, p = 0.45) or cardiovascular mortality (HR 0.97, 95% CI 0.62-1.52, p = 0.90) compared to GDMT. Neither CABG (HR 0.74, 95% CI 0.51-1.08, p = 0.13) nor PCI (HR 0.98, 95% CI 0.62-1.55, p = 0.93) demonstrated a mortality reduction compared to GDMT. Both groups experienced significant reductions in LV size and improvements in LVEF, greater in the revascularization group. Revascularization did not outperform GDMT in ischaemic LV dysfunction following HF admission in this retrospective analysis. Larger prospective studies are needed to clarify the potential role of revascularization in improving outcomes.