Abstract 18409: Longer Ambulatory Monitoring Increases Identification of Clinically Significant Ectopy

Abstract

Introduction: Frequent premature ventricular contractions (PVCs) can cause a reversible reduction in left ventricular systolic function. Prior studies have found that this cardiomyopathy is associated with PVC counts exceeding 13-37% of total heart beats. Most of these studies used 24-hour ambulatory electrocardiograms (AECG) to assess PVC burden; however, PVC counts may vary across 24-hour periods. Hypothesis: Extended monitoring with AECG will improve detection of clinically significant ectopy. Methods: Records from all patients receiving 14-day AECGs at the San Francisco Veterans Affairs Medical Center between March 2012 and March 2015 (N=694) were reviewed and those with total PVC counts ≥ 1.0% of total heart beats were included (N= 105). Each patient’s daily PVC count was abstracted, and the range of these values across 24-hour periods was assessed. The median time for these ranges to cross clinically significant thresholds (PVCs ≥ 10, 15 or 20% of total heart beats) was determined. Results: Median PVC burden was 2.8% of total heart beats (interquartile range, IQR 1.8-6.8%) and the median range across 24-hour periods was 4.7% (IQR 2.9-10.4%). Individual ranges of daily PVC burden crossed thresholds of 10, 15 and 20% of total heart beats in 23.8%, 17.1% and 12.4% of patients, respectively. Median time to detecting an individual’s maximum PVC burden was 6 days (IQR 2-11 days). While 88% of those who reached the 20% threshold did so on the first day of monitoring, only 53% of those reaching the 10% threshold did similarly, with a continually increasing yield throughout the 14 day monitoring period (Figure). Conclusions: Individual PVC burden varies widely from day-to-day. While the majority of patients who ultimately crossed clinically significant thresholds did so on the first day of monitoring, extended monitoring nearly doubled those reaching the 10% threshold.