@article {5850, title = {Atrial fibrillation and the risk of sudden cardiac death: the atherosclerosis risk in communities study and cardiovascular health study.}, journal = {JAMA Intern Med}, volume = {173}, year = {2013}, month = {2013 Jan 14}, pages = {29-35}, abstract = {

BACKGROUND: It is unknown whether atrial fibrillation (AF) is associated with an increased risk of sudden cardiac death (SCD) in the general population. This association was examined in 2 population-based cohorts.

METHODS: In the Atherosclerosis Risk in Communities (ARIC) Study, we analyzed data from 15 439 participants (baseline age, 45-64 years; 55.2\% women; and 26.6\% black) from baseline (1987-1989) through December 31, 2001. In the Cardiovascular Health Study (CHS), we analyzed data from 5479 participants (baseline age, >=65 years; 58.2\% women; and 15.4\% black) from baseline (first cohort, 1989-1990; second cohort, 1992-1993) through December 31, 2006. The main outcome was physician-adjudicated SCD, defined as death from a sudden, pulseless condition presumed to be due to a ventricular tachyarrhythmia. The secondary outcome was non-SCD (NSCD), defined as coronary heart disease death not meeting SCD criteria. We used Cox proportional hazards models to assess the association between AF and SCD/NSCD, adjusting for baseline demographic and cardiovascular risk factors.

RESULTS: In the ARIC Study, 894 AF, 269 SCD, and 233 NSCD events occurred during follow-up (median, 13.1 years). The crude incidence rates of SCD were 2.89 per 1000 person-years (with AF) and 1.30 per 1000 person-years (without AF). The multivariable hazard ratios (HRs) (95\% CIs) of AF for SCD and NSCD were 3.26 (2.17-4.91) and 2.43 (1.60-3.71), respectively. In the CHS, 1458 AF, 292 SCD, and 581 NSCD events occurred during follow-up (median, 13.1 years). The crude incidence rates of SCD were 12.00 per 1000 person-years (with AF) and 3.82 per 1000 person-years (without AF). The multivariable HRs (95\% CIs) of AF for SCD and NSCD were 2.14 (1.60-2.87) and 3.10 (2.58-3.72), respectively. The meta-analyzed HRs (95\% CIs) of AF for SCD and NSCD were 2.47 (1.95-3.13) and 2.98 (2.52-3.53), respectively.

CONCLUSIONS: Incident AF is associated with an increased risk of SCD and NSCD in the general population. Additional research to identify predictors of SCD in patients with AF is warranted.

}, keywords = {Aged, Atrial Fibrillation, Cardiovascular Diseases, Death, Sudden, Cardiac, Demography, Ethnic Groups, Female, Humans, Incidence, Male, Middle Aged, Proportional Hazards Models, Risk Assessment, Risk Factors, Sex Factors, United States}, issn = {2168-6114}, doi = {10.1001/2013.jamainternmed.744}, author = {Chen, Lin Y and Sotoodehnia, Nona and B{\r u}zkov{\'a}, Petra and Lopez, Faye L and Yee, Laura M and Heckbert, Susan R and Prineas, Ronald and Soliman, Elsayed Z and Adabag, Selcuk and Konety, Suma and Folsom, Aaron R and Siscovick, David and Alonso, Alvaro} } @article {7243, title = {Development and Validation of a Sudden Cardiac Death Prediction Model for the General Population.}, journal = {Circulation}, volume = {134}, year = {2016}, month = {2016 Sep 13}, pages = {806-16}, abstract = {

BACKGROUND: Most sudden cardiac death (SCD) events occur in the general population among persons who do not have any prior history of clinical heart disease. We sought to develop a predictive model of SCD among US adults.

METHODS: We evaluated a series of demographic, clinical, laboratory, electrocardiographic, and echocardiographic measures in participants in the ARIC study (Atherosclerosis Risk in Communities) (n=13 677) and the CHS (Cardiovascular Health Study) (n=4207) who were free of baseline cardiovascular disease. Our initial objective was to derive a SCD prediction model using the ARIC cohort and validate it in CHS. Independent risk factors for SCD were first identified in the ARIC cohort to derive a 10-year risk model of SCD. We compared the prediction of SCD with non-SCD and all-cause mortality in both the derivation and validation cohorts. Furthermore, we evaluated whether the SCD prediction equation was better at predicting SCD than the 2013 American College of Cardiology/American Heart Association Cardiovascular Disease Pooled Cohort risk equation.

RESULTS: There were a total of 345 adjudicated SCD events in our analyses, and the 12 independent risk factors in the ARIC study included age, male sex, black race, current smoking, systolic blood pressure, use of antihypertensive medication, diabetes mellitus, serum potassium, serum albumin, high-density lipoprotein, estimated glomerular filtration rate, and QTc interval. During a 10-year follow-up period, a model combining these risk factors showed good to excellent discrimination for SCD risk (c-statistic 0.820 in ARIC and 0.745 in CHS). The SCD prediction model was slightly better in predicting SCD than the 2013 American College of Cardiology/American Heart Association Pooled Cohort risk equations (c-statistic 0.808 in ARIC and 0.743 in CHS). Only the SCD prediction model, however, demonstrated similar and accurate prediction for SCD using both the original, uncalibrated score and the recalibrated equation. Finally, in the echocardiographic subcohort, a left ventricular ejection fraction <50\% was present in only 1.1\% of participants and did not enhance SCD prediction.

CONCLUSIONS: Our study is the first to derive and validate a generalizable risk score that provides well-calibrated, absolute risk estimates across different risk strata in an adult population of white and black participants without a clinical diagnosis of cardiovascular disease.

}, issn = {1524-4539}, doi = {10.1161/CIRCULATIONAHA.116.023042}, author = {Deo, Rajat and Norby, Faye L and Katz, Ronit and Sotoodehnia, Nona and Adabag, Selcuk and deFilippi, Christopher R and Kestenbaum, Bryan and Chen, Lin Y and Heckbert, Susan R and Folsom, Aaron R and Kronmal, Richard A and Konety, Suma and Patton, Kristen K and Siscovick, David and Shlipak, Michael G and Alonso, Alvaro} }