Abstract Body (Do not enter title and authors here): Introduction
While implantable cardiac defibrillators (ICDs) can prevent sudden arrhythmic death (SAD), less than 30% of SAD patients meet criteria for implantation. Improved risk stratification and prediction is necessary to identify individuals at risk.

Objective
The purpose of this study was to evaluate the role of high-sensitivity troponin T (hs-TnT) and high sensitivity troponin I (hs-TnI) in predicting SAD.

Methods
We prospectively evaluated the associations of hs-TnT and hs-TnI with the incidence of SAD in 5,764 participants enrolled in the PREDETERMINE study, which enrolled individuals with history of coronary artery disease (CAD) not meeting criteria for ICD implantation with left ventricular ejection fraction (LVEF) above 30%. Using multivariable Cox proportional hazards models, hs-TnT and hs-TnI were evaluated as continuous (log-transformed) variables, by quintile, and dichotomously by clinical thresholds. Spearman coefficients were calculated to assess biomarker correlations.

Results
Over a median 8.1 years follow-up, 4.3% (n=249) of the study cohort experienced SAD. Within our cohort, hs-TnT and hs-TnI were highly correlated with a Spearman coefficient of 0.77. After multivariable adjustment, both hs-TnT and hs-TnI were associated with increased risk of SAD (HR 1.18, 95% CI 1.03-1.36 per 1-SD change for hs-TnT, and HR 1.19, 95% CI 1.04-1.37 per 1-SD change for hs-TnI). Risk for SAD was elevated in the highest quintile of hs-TnT (HR 2.53, 95% CI 1.47-4.37) and the highest quintile of hs-TnI (HR 3.23, 95% CI 1.86-5.60) compared to the lowest quintile. Elevated hs-TnT ≥19 ng/L (median) was associated with increased risk of SAD (1.69, 95% CI 1.27-2.25), as was hs-TnI ≥ 8.5 ng/L (HR 1.69, 95% CI 1.29-2.23).

Conclusion
In our large, prospectively enrolled cohort of participants with CAD and LVEF above 30%, both increased hs-TnT and hs-TnI were each significantly associated with similarly increased risks of SAD. Among individuals who are at risk for SAD but do not qualify for prevention with ICD implantation, measurement of high-sensitivity troponin in conjunction with clinical data may help to identify those most likely to benefit from preventative therapy.