Abstract 2091: Diabetes Mellitus Reduces Exercise Capacity and Heart Rate Variability in Patients with Heart Failure
Background: In heart failure (HF), poor exercise capacity and autonomic dysfunction are predictors of poor survival. Autonomic dysfunction is linked with diabetes mellitus (DM). The influence of DM on peak oxygen consumption (VO2) has been evaluated, but little is known about its effect on other exercise parameters. We sought to determine the effects of DM on aerobic exercise capacity and time-domain heart rate variability (HRV) in patients with moderate HF.
Methods: In a cross-sectional study, 77 HF patients (76 [99%] male; aged 62.7 ± 10.7 years; EF 27 ± 9%; 62 [80%] NYHA II, 15 [20%] NYHA III–IV) were compared by DM status: DM+ (N= 26) and DM- (N= 51). Presence of DM was identified by baseline chart review. Aerobic exercise capacity parameters were gathered via maximal bicycle cardiopulmonary exercise testing: 1) peak VO2, heart rate (HR), and workload, 2) VO2, ventilatory threshold, and 3) exercise duration. Time domain measures of HRV were obtained from 24-hour Holter ECG recording: 1) standard deviation of all normal sinus interval over 24 hours (SDNN), 2) standard deviation of the average normal 5-minute R-R interval (SDANN), 3) root-mean-square of successive normal sinus RR interval difference (rMSSD), and 4) percentage of successive normal sinus RR intervals >50 ms (pNN50). Between-group differences were identified by t-test and Chi Square. There were no between-group differences in age, EF, or NYHA class.
Results: Compared to DM− patients, DM+ patients had lower aerobic exercise capacity parameters on all measures except peak HR (see Table⇓). Time-domain HRV was also lower in DM+ patients on all measures.
Conclusion: In moderate HF, DM may further diminish exercise capacity and autonomic dysfunction already compromised by HF. Therefore, clinicians should tailor exercise prescriptions carefully for HF patients with DM and should consider interventions to improve exercise capacity and HRV in patients with both HF and DM. Between-Group Difference: Exercise Capacity & Time-Domain HRV