Abstract Aims Improved risk stratification to identify non-ischaemic heart failure patients who will benefit from primary prophylactic implantable cardioverter-defibrillator (ICD) is needed. We examined the potential of ventricular arrhythmia to identify patients who could benefit from an ICD. Methods and results A total of 850 non-ischaemic systolic heart failure patients with left ventricle ≤35% and elevated N-terminal pro-brain natriuretic peptides had a 24-h Holter monitor recording performed. We examined present non-sustained ventricular tachycardia (NSVT), defined as ≥3 consecutive premature ventricular contractions (PVCs) with a rate of ≥100/min, and number of PVCs per hour stratified into low (<30) and high burden (≥30) groups. Outcome measures were overall mortality, sudden cardiac death (SCD), and cardiovascular death (CVD). In total, 193 patients died, 49 from SCD and 125 from CVD. Non-sustained ventricular tachycardia (365 patients) was significantly associated with increased all-cause mortality hazard ratio (HR) 1.47; 95% confidence interval (CI) 1.07–2.03; P = 0.02 and to CVD (HR 1.89; CI 1.25–2.87; P = 0.003). High burden PVC (352 patients) was associated with increased all-cause mortality (HR1.38; CI 1.00–1.90; P = 0.046) and with CVD (HR 1.78; CI 1.19–2.66; P = 0.005). There was no statistically significant association with SCD for neither NSVT nor PVC. In interaction analyses, neither NSVT (P = 0.56) nor high burden of PVC (P = 0.97) was associated with survival benefit from ICD implantation. Conclusion Ventricular arrhythmia in non-ischaemic heart failure patients was associated with a worse prognosis but could not be used to stratify patients to ICD implantation.