Aims
While clinical trials have suggested that a high ventricular rate is associated with increased risk of heart failure (HF) and mortality, all-comers studies are warranted.

Objective
To assess 1-year risk of new-onset diagnosed HF and all-cause mortality among rate-control treated patients presenting with atrial fibrillation (AF) on an electrocardiogram (ECG) according to ventricular rate.

Methods and results
ECGs recorded at the Copenhagen General Practitioners Laboratory (2001–15) were used to identify patients with AF. Multivariate Cox proportional hazard regression models were used to compare risk of new-onset HF and all-cause mortality after first ECG presenting with AF according to ventricular rate on ECG [<60, 60–79, 80–99, and 100–110, > 110 beats per minute (bpm)]. We identified 7408 patients in treatment with rate control drugs at time of first ECG presenting with AF [median age 78 years (Q1,Q3 = 70–85 years)], 45.8% male, median ventricular rate 83 bpm, (Q1,Q3 = 71–101 bpm)]. During 1-year follow-up, 666 (9.0%) of all patients with AF developed HF and 858 (11.6%) died. Patients with AF ventricular rates 100–110 bpm and >110 bpm had a hazard ratio (HR) of 1.46 (CI: 1.10–1.95) and 2.41 (CI: 1.94–3.00) respectively for new-onset HF, compared with 60–79 bpm. Similarly, patients with AF ventricular rates 100–110 bpm and >110 bpm had a HR of 1.44 (CI: 1.13–1.82) and 1.34 (CI: 1.08–1.65) respectively for all-cause mortality, compared with 60–79 bpm.

Conclusions
Ventricular rates ≥100 bpm among patients presenting with AF on ECG in treatment with rate control drugs were associated with greater risk of both new-onset HF and all-cause mortality.