January 22, 2021Open Access
View Full PaperExercise Ventricular Rates, Cardiopulmonary Exercise Performance, and Mortality in Patients With Heart Failure With Atrial Fibrillation
Key Result
Lower peak exercise ventricular rate was associated with higher 10-year all-cause mortality compared to higher peak rate (HR 2.56; 95% CI 1.62-4.04) in heart failure with atrial fibrillation.
Study Design
Type
Cohort (n=903)
Structured PICO
Are resting and exercise ventricular rates associated with exercise capacity and mortality in patients with heart failure and atrial fibrillation?
P
Population
903 patients with heart failure (HF) and atrial fibrillation (AF) referred for cardiopulmonary stress testing, median age 60, 76.1% male, median LVEF 25%.
O
Outcome
Peak oxygen consumption (PVO2) ≤18 mL/kg per minute, continuous PVO2, and 10-year all-cause mortalityhard clinical
In patients with heart failure and atrial fibrillation, lower exercise ventricular rate parameters are associated with worse exercise capacity and higher long-term mortality, whereas resting ventricular rate is only associated with exercise capacity.
Main Result
Effect estimate: HR 2.56 (95% CI 1.62-4.04)
Abstract
Background: In heart failure (HF) with sinus rhythm, resting and exercise heart rates correlate with exercise capacity and mortality. However, in HF with atrial fibrillation (AF), this correlation is unknown. Our aim is to investigate the association of resting and exercise ventricular rates (VRs) with exercise capacity and mortality in HF with AF. Methods: We identified 903 patients with HF and AF referred for cardiopulmonary stress testing. AF was defined as history of AF and AF during cardiopulmonary stress testing. We constructed multivariable models to evaluate the association of resting VR, peak exercise VR, VR reserve (peak VR−resting VR), and chronotropic index with (1) peak oxygen consumption (PVO 2 ) ≤18 mL/kg per minute, (2) continuous PVO 2 , and (3) 10-year all-cause mortality. Results: Median (25th–75th percentile) age was 60 (52–67) years, left ventricular ejection fraction was 25 (15–50)%, and 76.1% were males. Patients with lower (quartile 1) compared with higher (quartile 4) peak VR, VR reserve, and chronotropic index were more likely to have PVO 2 ≤18 mL/kg per min (adjusted odds ratio 95% CI: 14.92 8.07–27.58, 24.60 12.36–48.98, and 22.31 11.24–44.27, respectively), and higher all-cause mortality (adjusted hazard ratio 95% CI: 2.56 1.62–4.04, 2.29 1.47–3.59, and 2.30 1.51–3.49, respectively). For every 10 beats per minute increase in VR reserve, PVO 2 increased by 1.05 mL/kg per minute (B-coefficient 95% CI: 1.05 0.94–1.15) and mortality decreased by 12% (adjusted hazard ratio 95% CI: 0.88 0.83–0.94). Resting VR was associated with PVO 2 (B-coefficient 95% CI: −0.46 −0.70 to −0.23) but not mortality (adjusted hazard ratio 95% CI: 0.97 0.88–1.06). Conclusions: In patients with HF and AF, higher resting VR and lower peak exercise VR, VR reserve, and chronotropic index were all associated with worse peak exercise capacity, but only lower exercise VR parameters were associated with higher mortality. Dedicated studies are needed to gauge whether modulating exercise VR enhances exercise performance and outcomes.