Abstract 14635: Prognostic Value of Heart Rate Variability in Black Americans: The Jackson Heart Study

Abstract

Background: The prognostic value of heart rate variability (HRV) in Black Americans (BAs), who have distinct cardiac risk profiles, is not well studied. We aimed to investigate the association between HRV, all-cause mortality, and cardiovascular events in the Jackson Heart Study (JHS). Methods: We analyzed data from JHS participants who had HRV readings at baseline (2000-2004). HRV was measured as the standard deviation between subsequent R-waves on a 12-lead EKG. Data were analyzed up to December 31, 2014. Outcomes of interest were all-cause mortality and cardiovascular events (composite of incident stroke and coronary heart disease). Cox regression models were used to estimate hazard ratios (HRs) for the hazard of events in participants with an HRV below the median versus those with an HRV above the median. Restricted cubic splines (RCS) were used to explore non-linear interactions. All analyses were adjusted for age, sex, smoking, clinically relevant comorbidities, and risk factors. Results: Among the 3627 participants (mean age: 55.1 years; female: 62.4%), the median [IQR] HRV was 22.3ms [13.7, 36.1]. At baseline, participants with HRV below the median had a higher prevalence of several cardiometabolic diseases. Adjusted Cox regression showed that HRV below the median was associated with a 32% increased hazard of all-cause mortality (HR: 1.32 [1.09, 1.60]; P = 0.005) and a non-significant increase in incident cardiovascular events (HR: 1.28 [0.99, 1.66]; P = 0.059); Figure 1A . RCS suggested HRV has a non-linear relationship with all-cause mortality (P-nonlinearity: 0.0076) and cardiovascular events (P-nonlinearity: 0.0162), with the hazard of events beginning to increase sharply at HRV <25ms ( Figure 1B ). Conclusion: BAs had a higher mortality hazard associated with lower HRV readings, specifically <25ms. Consumer wearable sensors commonly record HRV, and our findings suggest that HRV could serve as a practical prognostic tool for this population.