Low Heart Rate Variability in a 2-Minute Electrocardiogram Recording Is Associated with an Increased Risk of Sudden Cardiac Death in the General Population: The Atherosclerosis Risk in Communities Study

<div><p>Low heart rate variability (HRV) has been linked to increased total mortality in the general population; however, the relationship between low HRV and sudden cardiac death (SCD) is less well-characterized. The goal of this study was to evaluate the relationship between low HRV and SCD in a community-based cohort. Our cohort consisted of 12,543 participants from the Atherosclerosis Risk in Communities (ARIC) study. HRV measures were derived from 2-minute electrocardiogram recordings obtained during the baseline exam (1987–89). Time domain measurements included the standard deviation of all normal RR intervals (SDNN) and the root mean squared successive difference (r-MSSD). Frequency domain measurements included low frequency power (LF) and high frequency (HF) power. During a median follow-up of 13 years, 215 SCDs were identified from physician adjudication of all coronary heart disease deaths through 2001. In multivariable adjusted Cox proportional hazards models, each standard deviation decrement in SDNN, LF, and HF were associated with 24%, 27% and 16% increase in SCD risk, respectively. Low HRV is independently associated with increased risk of SCD in the general population.</p></div

Predictors of sudden cardiac death in atrial fibrillation: The Atherosclerosis Risk in Communities (ARIC) study

<div><p>We previously reported that incident atrial fibrillation (AF) is associated with an increased risk of sudden cardiac death (SCD) in the general population. We now aimed to identify predictors of SCD in persons with AF from the Atherosclerosis Risk in Communities (ARIC) study, a community-based cohort study. We included all participants who attended visit 1 (1987–89) and had no prior AF (n = 14,836). Incident AF was identified from study electrocardiograms and hospitalization discharge codes through 2012. SCD was physician-adjudicated. We used cause-specific Cox proportional hazards models, followed by stepwise selection (backwards elimination, removing all variables with p>0.10) to identify predictors of SCD in participants with AF. AF occurred in 2321 (15.6%) participants (age 45–64 years, 58% male, 18% black). Over a median of 3.3 years, SCD occurred in 110 of those with AF (4.7%). Predictors of SCD in AF included higher age, body mass index (BMI), coronary heart disease, hypertension, diabetes, current smoker, left ventricular hypertrophy, increased heart rate, and decreased albumin. Predictors associated only with SCD and not other cardiovascular (CV) death included increased BMI (HR per 5-unit increase, 1.15, 95% CI, 0.97–1.36, p = 0.10), increased heart rate (HR per SD increase, 1.18, 95% CI 0.99–1.41, p = 0.07), and low albumin (HR per SD decrease 1.23, 95% CI 1.02–1.48, p = 0.03). In the ARIC study, predictors of SCD in AF that are not associated with non-sudden CV death included increased BMI, increased heart rate, and low albumin. Further research to confirm these findings in larger community-based cohorts and to elucidate the underlying mechanisms to facilitate prevention is warranted.</p></div

Baseline Participant Characteristics by Sudden Cardiac Death Status, Atherosclerosis Risk in Communities Study, 1987–2001.

<p>Baseline Participant Characteristics by Sudden Cardiac Death Status, Atherosclerosis Risk in Communities Study, 1987–2001.</p

Parsimonious multivariable cox proportional hazard model^* for prediction^† of SCD and non-sudden CV death in participants with AF in the ARIC study.

<p>Parsimonious multivariable cox proportional hazard model^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0187659#t003fn002" target="_blank">*</a>} for prediction<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0187659#t003fn003" target="_blank">^†</a> of SCD and non-sudden CV death in participants with AF in the ARIC study.</p

Hazard Ratios of Sudden Cardiac Death for Heart Rate Variability Measures, Atherosclerosis Risk in Communities Study, 1987–2001.

<p>Hazard Ratios of Sudden Cardiac Death for Heart Rate Variability Measures, Atherosclerosis Risk in Communities Study, 1987–2001.</p

Heart Rate Variability Measures and Sudden Cardiac Death Risk.

<p>Association between heart rate variability measures and sudden cardiac death incidence presented as hazard ratios (solid line) and 95% confidence intervals (shaded area). Results from Cox proportional hazards model with heart rate variability measures modeled using restricted cubic splines, adjusted for age, sex, and race. Median value of heart rate variability measures was considered the reference (HR = 1). The x-axis is presented using an inverted scale.</p

Atrial Fibrillation and Colonic Neoplasia in African Americans

<div><p>Background</p><p>Colorectal cancer (CRC) and atrial fibrillation/flutter (AF) share several risk factors including increasing age and obesity. However, the association between CRC and AF has not been thoroughly examined, especially in African Americans. In this study we aimed to assess the prevalence of AF and its risk factors in colorectal neoplasia in an African American.</p><p>Methods</p><p>We reviewed records of 527 African American patients diagnosed with CRC and 1008 patients diagnosed with benign colonic lesions at Howard University Hospital from January 2000 to December 2012. A control group of 731 hospitalized patients without any cancer or colonic lesion were randomly selected from the same time and age range, excluding patients who had diagnosis of both CRC and/or adenoma. The presence or absence of AF was based upon ICD-9 code documentation. The prevalence of AF in these three groups was compared by multivariate logistic regression.</p><p>Results</p><p>The prevalence of AF was highest among CRC patients (10%) followed by adenoma patients (7.2%) then the control group (5.4%, P for trend = 0.002). In the three groups of participants, older age (P<0.008) and heart failure (P<0.001) were significantly associated with higher risk of AF. After adjusting for these risk factors, CRC (OR: 1.4(95%CI):0.9–2.2, P = 0.2) and adenoma (OR: 1.1(95%CI):0.7–1.6, P = 0.7) were not significantly associated AF compared to control group.</p><p>Conclusions</p><p>AF is highly prevalent among CRC patients; 1 in 10 patients had AF in our study. The predictors of AF in CRC was similar to that in adenoma and other patients after adjustment for potential confounders suggesting that the increased AF risk in CRC is explained by higher prevalence of AF risk factors.</p></div

Multivariable cox proportional hazard ratios (95% confidence interval)^* for SCD and non-sudden CV death in ARIC participants with incident AF.

<p>Multivariable cox proportional hazard ratios (95% confidence interval)^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0187659#t002fn002" target="_blank">*</a>} for SCD and non-sudden CV death in ARIC participants with incident AF.</p

Characteristics of ARIC study participants at visit preceding AF diagnosis, stratified by mode of death.

<p>Characteristics of ARIC study participants at visit preceding AF diagnosis, stratified by mode of death.</p

Baseline characteristics of ARIC participants (n = 14,222), 1987–1989.

<p>Values are % for categorical variables and mean (SD) for continuous variables. BMI: Body mass index. CHD: Coronary heart disease. DHA: Docosahexaenoic acid. ECG: Electrocardiogram. EPA: Eicosapentanoic acid.</p