We hypothesized that an inadequate increase in heart rate (HR) during exercise was associated with low peak oxygen uptake (VO2 peak) seen in left ventricular assist device (LVAD) recipients and aimed to analyze the potential relation between HR and VO2 peak and use of drugs with negative chronotropic effect. Sixty-eight LVAD recipients (44 Heartmate 2 and 24 HVAD) with support duration >1 month and a VO2 peak were included from two centers. Patients were 57 ± 13 years at time of VO2 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 VO2 peak (r = 0.244, p = 0.045). Predicted heart rate reserve was associated with %Predicted VO2 peak (P = 0.011). Chronotropic incompetence (CI) was observed in 44% and VO2 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 VO2 peak and %HRR (r = 0.33, p = 0.024). In conclusion, almost half of LVAD recipients suffer from CI which is associated with lower VO2 peak. This relation did not seem to be affected by BB therapy.
From the *Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
†Department of Cardiology, Johns Hopkins University Hospital, Baltimore, Maryland
‡Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina.
Submitted for consideration October 2018; accepted for publication in revised form December 2018.
Dr. Gustafsson received a speaker’s fee from Abbott. Dr. Russell is on the Data and Safety Monitoring Board for Abbott. Drs. Mirza and Gustafsson received a grant from Jascha Fonden (No. 6186).
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Correspondence: Kiran K. Mirza, Department of Cardiology, B9441, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej no. 9, DK-2100 Copenhagen, Denmark. Email: RNZ440@alumni.ku.dk.