Long-Term Change in Cardiorespiratory Fitness in Relation to Atrial Fibrillation and Heart Failure (from the Kuopio Ischemic Heart Disease Risk Factor Study)

The benefits of aerobic fitness in relation to all-cause and cardiovascular mortality is well established; however, the associations of long-term change in cardiorespiratory fitness (CRF) with incident heart failure (HF) and atrial fibrillation (AF) have not been studied before. The Kuopio Ischaemic Heart Disease Risk Factor Study is a prospective cohort comprising men aged 42 to 60 years from the city of Kuopio and its surroundings, with a baseline examination between 1984 and 1989 (V1), a re-examination at 11 years (V2), and up to 15 years of follow-up from V2. CRF, as assessed by VO₂max, was measured at both visits using respiratory gas exchange during maximal exercise tolerance test. The difference (ΔVO₂max) was estimated as VO₂max (V2) − VO₂max (V1). Participants with no missing data on both baseline and 11-year exercise test were included (n = 481). The mean ΔVO₂max was −5.4 ml/min⋅kg (standard deviation 5.4). During a median follow-up of 14.3 years (interquartile range 13.3 to 15.1), 46 incident HF (9.6%) and 73 incident AF (15.2%) events were recorded. In a multivariate analysis adjusted for baseline age, baseline VO₂max, systolic blood pressure, smoking, type 2 diabetes, and cardiovascular disease, per 1 ml/min⋅kg higher ΔVO₂max was log linearly associated with incident HF with a 10% relative risk reduction of HF (hazard ratio 0.90, 95% confidence interval 0.83 to 0.97). No significant relation of ΔVO₂max with incident AF was observed. In conclusion, overall long-term improvement in CRF is associated with reduced risk of HF, indicating the importance of maintaining good CRF over time.