Abstract 3125: Association of Holter-Based Measures and Sudden Cardiac Death in the Community-Dwelling Elderly: The Cardiovascular Health Study
Sudden cardiac death (SCD) is the most common first manifestation of cardiovascular disease. Identification of those in the population who are at increased risk is of critical importance. Holter monitoring is an attractive source of information including: VPC counts, heart rate variability (HRV), heart rate turbulence (HRT) and T-wave alternans (TWA).
Methods: The Cardiovascular Healthy Study (CHS) is an NIH-sponsored population-based longitudinal study to identify risk factors for coronary heart disease and stroke those aged ≥65 years. N=49 (of 1649) participants, in normal sinus rhythm with usable Holter data, suffered SCD during up to 14 years of follow up. Holters were analyzed to research standards. They were matched by age, gender, beta-blocker use, history of MI and use of hypoglycemic medications with 2 control participants alive at the time of death of the case and not suffering SCD on follow up. Univariate and multivariate conditional logistic regression determined the association of Holter-based information and SCD.
Results: In univariate models, increased VPCs predicted SCD (RR=4.6, 95% CI =2.0–10.8, p<0.001) among those in the upper (>31 per 24 hours) compared to the lower half of VPC counts. Time domain HRV did not predict SCD. In the frequency domain, decreased normalized low frequency power (NLF, RR=0.96, 95% CI= (0.92– 0.99, p=0.015) predicted SCD. Decreased short-term fractal scaling exponent (DFA1) also predicted SCD (RR=0.08, 95% CI=0.01– 0.6, p=0.012). Having abnormal HRT onset or slope compared to having both factors normal or having <5 VPCs (RR=2.4, 95% CI=1.1–5.4, p=0.026) and having TWA ≥37 μV on Ch2 (RR=2.8, 95% CI=1.1–7.1, p=0.034) were also associated with SCD in univariate models. In multivariate models, being in the upper half of VPCs (RR=6.6, 95% CI=2.3–19.1, p<0.001) and having TWA ≥37 μV on ch2 (RR=4.8, 95% CI=1.5–15.8, p=0.009) or being in the upper half of VPCs (RR=6.4, 95% CI=2.1–20.2, p=0.001) and having decreased DFA1 (RR=0.07, 95% CI=0.01– 0.7, p=0.022) were significantly associated with SCD.
Conclusions: Results support the potential role of markers obtained from 24-hour Holter recording to identify older adults at increased risk of SCD.