Changes in cardiorespiratory fitness in non-permanent atrial fibrillation and quality of life
A B Sellevold, J M Letnes, R Byrkjeland, F P Brown, J P Loennechen, B M NesAbstract
Introduction
Evaluating symptoms and quality of life is essential for clinical management of atrial fibrillation (AF). The Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire scores symptoms, daily activities and treatment concerns, and produces a combined overall score. A change of ≥5 points in AFEQT is considered important. Cardiorespiratory fitness (CRF) is associated with beneficial health outcomes, but the impact of change in CRF on change in AFEQT is not well known.
Purpose
In this secondary analysis of a multicenter randomized controlled trial (exercise training vs. control) in patients with non-permanent AF (NEXAF trial), we assess the associations between change in CRF and change in AFEQT as well as potential differences between the two intervention groups.
Methods
We used multivariable linear regression to examine the association between change in VO2peak and change in AFEQT scores from baseline to 12 months. Change in VO2peak was modelled as a continuous variable expressed as percent of age- and sex-predicted values. Models were adjusted for baseline AFEQT, baseline VO2peak, age, sex, AF type, years since diagnosis, prior ablation, medication use, and heart failure. Effect modification by baseline VO2peak, sex, and intervention group was evaluated with interaction terms. Results are presented as adjusted mean differences with 95% confidence intervals (CIs).
Results
Among 261 participants with complete baseline and 12-month data, the mean age was 64±10 years, 30% were women, and 74% had paroxysmal AF. At baseline, the mean VO2peak was 81.2±16% of predicted, and the mean AFEQT overall score was 76.9±15.7. Greater increases in VO2peak were associated with greater improvements in AFEQT scores across domains in a dose–response manner (Fig. 1). No effect modification was observed according to baseline VO2peak, sex or intervention group (all p for interaction >0.24). The estimated increase in VO2peak required to achieve a clinically relevant 5-point improvement in AFEQT scores is shown in Table 1.
Conclusions
An increase in VO2peak (% predicted) was associated with an improvement in overall and domain-specific AFEQT scores. Neither baseline fitness level nor intervention arm affected this association.Figure 1