Cardiac autonomic dysfunction in breast cancer survivors.

Abstract

10057 Background: Cardiac autonomic dysfunction (AD) has been associated with increased cardiovascular (CV) and all-cause mortality in several diseases. We evaluated the prevalence, functional and prognostic significance of cardiac AD in a cohort of breast cancer (BC) survivors referred for exercise treadmill testing (ETT). Methods: Cardiac AD was defined as the presence of both an elevated resting heart rate (HR ≥ 80 beats per minute) and abnormal HR recovery (HRR ≤ 12 beats per minute if active cool down, or ≤ 18 beats per minute if passive recovery) at 1 minute after peak exercise. Presence of cardiac AD, exercise capacity, and all-cause mortality were assessed in 448 women (age 62.6±10.0 years), 8.7 [range 4.5, 14.3] years from BC diagnosis, compared to 448 cancer-free, age- and sex-matched controls, all of whom were clinically referred for ETT. Results: Elevated resting HR (23.7% vs. 17.0%, p = 0.013), abnormal HRR (25.9% vs. 20.3%, p = 0.048), and cardiac AD (8.0% vs. 4.2%, p = 0.025) were more prevalent in BC survivors than controls. BC survivors with cardiac AD had reduced exercise capacity compared to those without AD (Table). Among controls, cardiac AD was not associated with decreased exercise capacity. Among BC survivors (age-adjusted hazard ratio 1.90 (95% CI 0.78-4.62) and controls (age-adjusted hazard ratio 4.09 (95% CI 0.49-34.18), cardiac AD was not associated with increased all-cause mortality. Conclusions: Among patients referred for ETT, BC survivors have an increased prevalence of cardiac AD relative to controls. Cardiac AD is associated with decreased exercise capacity, but not increased all-cause mortality, in BC survivors. Available strategies to modulate cardiac AD may improve functional capacity in BC survivors. Table: Impact of markers of cardiac AD on exercise capacity. [Table: see text]