Effect of Heart Rate Reserve on Exercise Capacity in Patients Treated with a Continuous Left Ventricular Assist Device

摘要

Supplemental Digital Content is available in the text. We hypothesized that an inadequate increase in heart rate (HR) during exercise was associated with low peak oxygen uptake (VO_(2)peak) seen in left ventricular assist device (LVAD) recipients and aimed to analyze the potential relation between HR and VO_(2)peak and use of drugs with negative chronotropic effect. Sixty-eight LVAD recipients (44 Heartmate 2 and 24 HeartWare Ventricular Assist Device) with support duration >1 month and a VO_(2)peak were included from two centers. Patients were 57?±?13 years at time of VO_(2)peak and LVAD support duration was 483?±?545 days. Peak oxygen uptake was 12?±?4?ml/kg/min (40%?±?13% of predicted). Heart rate reserve (HRR = maximal HR ? resting HR) was 59?±?22 min~(?)~(1)(75% ± 15% of predicted for age, %HRR) and was significantly associated with VO_(2)peak (r = 0.244, p = 0.045). Predicted heart rate reserve was associated with %Predicted VO_(2)peak ( P = 0.011). Chronotropic incompetence (CI) was observed in 44% and VO_(2)peak was clearly lower in patients with CI (10?±?2.7 vs. 13?±?4.6?ml/kg/min, p = 0.005). Beta-blockers (BB) were prescribed to 85% and adjusting for being on target BB-dose did not affect the correlation between %predicted VO_(2)peak and %HRR (r = 0.33, p = 0.024). In conclusion, almost half of LVAD recipients suffer from CI which is associated with lower VO_(2)peak. This relation did not seem to be affected by BB therapy.