Abstract 1879: Device-Measured Autonomic Balance Predicts Mortality in Heart Failure Patients Receiving Cardiac Resynchronization Therapy
Background: The autonomic balance monitor (ABM) within a cardiac resynchronization therapy (CRT) device is a diagnostic heart rate variability metric derived from R-R interval measurements which assess sympathovagal balance, and perhaps may be used as a clinical predictor of mortality.
Methods: The relationship between ABM and mortality for patients enrolled in the CRT-RENEWAL Registry was examined. The average of weekly averages of ABM measurements prior to the 2-week wound check visit was evaluated. Associations of demographic and clinical history (age, gender, NYHA, diabetes, ejection fraction, and body mass index) with ABM were assessed using linear regression models, while the ABM and mortality association was explored via proportional hazards models. Survival distributions for patients above (“high”) and below (“low”) the median value of ABM were compared.
Results: Twenty-six deaths occurred among 347 of 1412 patients with ABM data available. The median (inter-quartile range) of ABM was 1.43 (0.63–2.78) and varied significantly by both gender and age (each p<0.05) with older patients and females having lower values. Lower ABM was associated with an increased risk of death (unadjusted hazard ratio per unit lower ABM = 2.68, p<0.01; adjusted hazard ratio per unit lower ABM = 2.73, p<0.01). No evidence suggests that the association between ABM and mortality varied by subgroups defined by demographic or clinical history variables (all p>0.20).
Conclusion: Females and those of advanced age were more likely to have lower ABM values and thus a lower probability of survival. Thus, the ABM feature may be useful in predicting mortality of patients with a CRT device.