The Axis, Burden, Coupling interval, Ventricular Tachycardia (ABC-VT) risk score was found to accurately predict adverse left ventricular (LV) remodeling as well as subsequent adverse events (AEs) in patients with frequent premature ventricular contractions (PVCs), according to study results published in Heart Rhythm.
Although PVC burden is generally considered the best predictor of the occurrence of cardiomyopathy in individuals who experience frequent PVCs, there is currently no validated risk stratification tool available for this population, and the optimal management strategy remains unclear for patients with preserved LV function.
In this retrospective analysis, 206 consecutive patients (mean age, 65±16 years; 61.7% men) with frequent PVCs (>5% burden) were enrolled between 2012 and 2017. Study participants underwent 14-day continuous patch monitoring and were given concurrent transthoracic echocardiography. Adverse LV remodeling was defined as LV ejection fraction (LVEF) <45% or LV end-diastolic volume index >75 mL/m2. Binary logistic regression was used to derive multivariable predictors of LV remodeling, and log odds ratios (ORs) of these predictors were used to establish the ABC-VT risk score.
The study’s primary outcome was a composite of AEs (cardiovascular mortality, heart failure hospitalization, or reduction in LVEF >10%). The risk score was validated in patients with preserved LV function (ie, LVEF >45%) in this original derivation cohort as well as within a Korean PVC registry (n=559).
The mean PVC burden in the derivation cohort was 11.6±6.2%, with substantial daily variation, with a minimum burden of 7.3%±6.2%, and a maximum burden of 17.9%±8.0%. There were 167 patients (81.1%) and 39 patients (18.9%) with preserved and diminished LVEF, respectively. The most common comorbidity was hypertension (52%). The strongest predictor of adverse remodeling was the daily minimum PVC burden (OR, 1.07; 95% CI, 1.02-1.12; P =.009).
The ABC-VT risk score was created based on the variables found to independently predict adverse LV remodeling. These included a PVC axis that was superiorly directed (OR, 2.70; 95% CI, 1.25-5.81; P =.01; 1 point), a 10% to 20% PVC burden (OR, 3.50; 95% CI, 1.39-8.82; P =.01; 2 points), a PVC burden >20% (OR, 4.40; 95% CI, 1.17-16.49; P =.03; 3 points), a coupling interval >500 ms (OR, 4.73; 95% CI, 2.19-10.21; P <.001; 4 points), and nonsustained VT (OR, 5.26; 95% CI, 2.09-13.23; P <.001; 4 points). Mean scores were 4.2±3.2 in the original cohort and 4.3±2.8 in the Korean cohort. This score was associated with future AEs in both the derivation cohort (hazard ratio [HR], 1.43; 95% CI, 1.19-1.73; P <.001) and the Korean cohort (HR, 1.22; 95% CI, 1.05-1.42; P =.01), with lower scores predicting a better prognosis.
Study limitations include its retrospective design and a lack of clarity regarding the nature and direction of the relationship between predictors and disease occurrence.
“The ABC-VT risk score is a simple score that, if validated prospectively, may allow
identification and early treatment of patients at risk of developing future cardiomyopathy,” noted the authors. They recommended that future research involve larger prospective trials to further validate their findings.
Voskoboinik A, Hadjis A, Alhede C, et al. Predictors of adverse outcome in patients with frequent premature ventricular complexes: The ABC-VT risk score. Heart Rhythm. 2020. doi:10.1016/j.hrthm.2020.02.020