No independently validated score currently exists for risk stratification of patients with frequent premature ventricular contractions (PVCs).The purpose of this study was to develop a risk score to predict adverse events in patients with frequent PVCs.We analyzed consecutive patients between 2012 and 2017 undergoing 14-day continuous monitoring with frequent PVCs (>5%) and concurrent echocardiography. We performed binary logistic regression to determine multivariate predictors of adverse left ventricular remodeling (left ventricular ejection fraction [LVEF] <45% or left ventricular end-diastolic volume index >75 mL/m). A risk score was created using the log(odds ratio) (OR) of these predictors and validated prospectively to determine the risk of future adverse events in those with baseline LVEF >45%. An adverse event was defined as LVEF decline by 10%, heart failure hospitalization, or cardiovascular mortality. Two validation cohorts were used: follow-up from the original derivation cohort (cohort 1) and an independent Korean PVC registry (cohort 2).2The derivation cohort comprised 206 patients with a mean PVC burden of 11.6% ± 6.2% and considerable daily fluctuation (minimum burden 7.3% ± 6.2% vs maximum 17.9% ± 8.0%). Independent predictors of adverse remodeling were as follows: superiorly directed PVC axis (OR 2.7; 1 point), PVC burden 10%-20% (OR 3.5; 2 points) and >20% (OR 4.4; 3 points), PVC coupling interval >500 ms (OR 4.7; 4 points), nonsustained ventricular tachycardia (OR 5.3; 4 points), which form the ABC-VT risk score. This score predicted future adverse events in both validation cohorts: cohort 1, hazard ratio 1.43; 95% confidence interval 1.19-1.73; P < .001 and cohort 2, hazard ratio 1.22; 95% confidence interval 1.05-1.42; P = .01.The ABC-VT score is a simple tool that predicts adverse left ventricular remodeling and future clinical deterioration in patients with frequent PVCs.