Receiver operating characteristic (ROC) curve and logistic regression models comparing number of risk factors and the addition of exercise to detect severe ventricular arrhythmias. The ROC curves for two logistic regression models. Model 1 includes the number of risk factors to detect risk of severe ventricular arrhythmia. Model 2 includes the number of risk factors and total lifetime exercise dose to detect the risk of severe ventricular arrhythmia. Adding total lifetime exercise dose to the model did not improve the detection of risk. The bar charts show the comparison of the area under the curve (AUC) of two logistic regression models. The table shows the odds ratios (OR) and P-values from the two logistic regression models. AIC, Akaike information criterion; AUC, area under the curve.