Fluctuations in premature ventricular contraction burden can affect medical assessment and management

Background: Frequent premature ventricular contractions (PVCs) can cause disabling symptoms and decrease left ventricular ejection fraction. PVC burden, typically quantified by a 24-hour monitor, is one of the factors that determines the clinical management of PVCs. Objective: The purpose of this study was to evaluate the extent of variability in 24-hour PVC burden during 14-day ambulatory cardiac monitoring in patients with significant PVC burden. Methods: All patients referred for PVC evaluation received a 14-day ambulatory cardiac monitor. Parameters of interest included mean 14-day PVC burden, minimum and maximum 24-hour PVC burden, and absolute change in 24-hour PVC burden (maximum minus minimum). We included only patients with a mean 14-day PVC burden of more than 5%. Results: Fifty-nine patients were included in the study. The median of mean 14-day PVC burden, maximum 24-hour PVC burden, and minimum 24-hour PVC burden were 9.0% (IQR 6.4%–17.9%), 16.2% (IQR 11.7%–26.2%), and 4.5% (IQR 2.6%–11.2%) respectively (P <.001). The median of the absolute 24-hour PVC burden change was 9.9% (IQR 5.4%–14.5%). There was a 2.45-fold (IQR 1.68- to 5.55-fold) median difference between maximum 24-hour PVC burden and minimum 24-hour burden in the same patient. When categorized by low (<10%), intermediate (10%–20%), and high (>20%) 24-hour PVC burden, 72.9% patients fell into at least 2 categories depending on the 24-hour period considered. Conclusion: There is a significant variation in 24-hour PVC burden when measured over a 14-day period in patients with of PVC burden of more than 5%. This variation might impact critical clinical decisions in a significant proportion of such patients.