Case-control study of heart rate abnormalities across the breast cancer survivorship continuum

Background Mechanisms underlying impaired exercise capacity and increased cardiovascular mortality observed in breast cancer (BC) patients remain unclear. The prevalence, functional, and prognostic significance of elevated resting heart rate (HR) and abnormal heart rate recovery (HRR) in breast cancer (BC) requires evaluation. Methods In a single‐center, retrospective, case‐control study of women referred for exercise treadmill testing (ETT), 448 BC patients (62.6 ± 10.0 years) were compared to 448 cancer‐free, age‐matched controls. Elevated resting HR was defined as HR ≥80 bpm at rest. Abnormal HRR at 1‐minute following exercise was defined as ≤12 bpm if active recovery or ≤18 bpm if passive recovery. Association of these parameters with exercise capacity and all‐cause mortality was evaluated. Results Elevated resting HR (23.7% vs 17.0%, P = 0.013) and abnormal HRR (25.9% vs 20.3%, P = 0.048) were more prevalent in BC cohort than controls. In adjusted analyses, BC patients with elevated resting HR (−0.9 METs (SE 0.3); P = 0.0003) or abnormal HRR (−1.3 METs (SE 0.3); P