Abstract Background The European Society of Cardiology (ESC) guidelines for the management of atrial fibrillation (AF) advise to treat AF according to the ABC pathway: A, anticoagulation, B, better symptom control, and C, comorbidities and cardiovascular risk factor management. Optimal treatment of comorbidities and risk factors slows AF progression and improves success rates of rhythm interventions for AF. However, several studies report underdiagnosis and therefore possible undertreatment for common cardiovascular comorbidities. Purpose This study aims to evaluate how common modifiable cardiovascular risk factors are managed in AF patients referred for catheter ablation. Methods This is a substudy of the ISOLATION study, a prospective cohort study including consecutive patients with paroxysmal or persistent AF referred for AF ablation. Screening for common modifiable risk factors for AF is structurally embedded in the work-up for AF ablation in the two participating centres. In the present study the prevalence of the following risk factors at this screening moment was assessed: (1) body mass index (BMI) above the target BMI for ablation (≥27 kg/m2), (2) hypertension, defined as on-site systolic blood pressure >130 mmHg and/or diastolic blood pressure >80 mmHg, (3) decreased glucose tolerance or diabetes mellitus, defined as HbA1c ≥6.5%, (4) dyslipidaemia, defined as low-density lipoprotein (LDL) ≥2.5 mmol/l, (5) regular alcohol consumption, defined as self-reported consumption of >15 standardized units/week, and (6) sleep disordered breathing (SDB), defined as apnoea-hypopnoea index (AHI) ≥15 assessed with home sleep tests (subset of patients). Results Among the 981 patients studied (median age 65 [59–71] years old, 64% male, 69% paroxysmal AF), previously diagnosed comorbidities were common (46% hypertension, 7% diabetes, 22% dyslipidaemia, 10% SDB), and a large proportion of patients received targeted treatment (Table 1). However, non-optimally managed risk factors remained significant (Figure 1). BMI ≥27 kg/m2 was present in 56% of patients. High systolic and diastolic blood pressure were present in 62% and 51% of patients, respectively, and any form of high blood pressure (either systolic or diastolic) was seen in 72% of patients. HbA1c was found to be above target ranges in 9% patients and LDL in 56%. A weekly alcohol consumption of ≥15 units was reported by 4% of patients. Screening for SDB was performed in a subset of patients (n=287), for whom AHI was ≥15 in 52%. Overall, 9% of patients had 4 or more non-optimally controlled modifiable risk factors, whereas the median number of modifiable risk factors was 2 [1–3]. Conclusions Structural screening revealed a high prevalence of non-optimally controlled modifiable cardiovascular risk factors in patients referred for AF catheter ablation. According to recent ESC guidelines, improving treatment of comorbidities may improve AF ablation success rates and even reduce mortality. Funding Acknowledgement Type of funding sources: None.