Abstract P018: Poincare Plot Asymmetry is Associated With Sudden Cardiac Death in the Community: The Atherosclerosis Risk in Community Study

Abstract

Introduction: Poincare plot asymmetry has been associated with sustained ventricular tachyarrhythmias, implicating involvement of the autonomic nervous system. An association between sudden cardiac death (SCD) and Poincare plot asymmetry has not previously been studied in a general population cohort. Porta index measures time asymmetry in heart rate variability (HRV), corresponding to disproportionate relative tachycardic predominance. Hypothesis: We hypothesized that increasing tachycardic asymmetry as measured by Porta Index is associated with SCD. Methods: We analyzed 10-second ECG in 14,247 participants across 5 visits in the Atherosclerosis Risk in Communities (ARIC) cohort (mean age 54.1±5.87y; 6,380 [45%] men; 10,569 [74%] white, 1,582 [11%] with prevalent cardiovascular disease (CVD)). Participants with atrial fibrillation, premature contractions, sinoatrial (SA) or atrioventricular (AV) blocks II-III were excluded. Only normal sinus beats were included in the semi-automated analysis. Accuracy of automated R-peak detection was manually validated. SCD, non-SCD, and non-cardiac death served as competing outcomes in a Fine and Gray competing risk model. Results: Overall, there was larger variability in Porta index within the same participant from visit to visit (50.0±12.1) than between different participants (50.0±8.4). Over median follow-up of 24.4 years, there were 497 SCDs (incidence 1.66 [95% CI 1.52-1.82], 742 non-SCD (incidence 2.48 [95%CI 2.31-2.67], and 3,753 non-cardiac deaths (incidence 12.6 [95% CI 12.1-13.0]) per 1,000 person-years. In time-updated analysis, Porta index was independently associated with increased risk of SCD (HR 1.13 [1.04-1.23]). Neither non-sudden cardiac death nor non-cardiac death are associated with Porta ndex. Conclusion: Time-updated Poincare Plot asymmetry as measured by Porta index, reflecting tachycardic runs longer than bradycardic runs, is independently associated with SCD in the community. Poincare plot asymmetry requires further study.