Early heart rate recovery after exercise predicts mortality in patients with chronic heart failure

Abstract Background Patients with chronic heart failure (CHF) have multiple abnormalities of autonomic regulation that have been associated to their high mortality rate. Heart rate recovery immediately after exercise is an index of parasympathetic activity, but its prognostic role in CHF patients has not been determined yet. Methods Ninety-two stable CHF patients (83M/9F, mean age: 51±12 years) performed an incremental symptom-limited cardiopulmonary exercise testing. Measurements included peak O 2 uptake (VO 2 p), ventilatory response to exercise (V E /VCO 2 slope), the first-degree slope of VO 2 for the 1st minute of recovery (VO 2 /t-slope), heart rate recovery [(HRR 1 , bpm): HR difference from peak to 1 min after exercise] and chronotropic response to exercise [%chronotropic reserve (CR, %)=(peak HR−resting HR/220−age−resting HR)×100]. Left ventricular ejection fraction (LVEF, %) was also measured by radionuclide ventriculography. Results Fatal events occurred in 24 patients (26%) during 21±6 months of follow-up. HRR 1 was lower in non-survivors (11.4±6.4 vs. 20.4±8.1; p 1 ≤12 bpm versus 11% in patients with HRR 1 >12 bpm (log-rank: 32.6; p 1 resulted as an independent predictor of mortality ( χ 2 =19.2; odds ratio: 0.87; p 2 p, V E /VCO 2 slope, CR and VO 2 /t-slope. In a subgroup of patients with intermediate exercise capacity (VO 2 p: 10–18, ml/kg/min), HRR 1 was a strong predictor of mortality ( χ 2 : 14.3; odds ratio: 0.8; p Conclusions Early heart rate recovery is an independent prognostic risk indicator in CHF patients and could be used in CHF risk stratification.