Diagnostic reliability of monitoring for premature atrial and ventricular complexes

Abstract

Background Short-term ambulatory ECG monitoring is often used to assess premature atrial complex (PAC) and premature ventricular complex (PVC) frequency, but the diagnostic reliability is unknown. Objective To study day-to-day variability of PAC and PVC frequency. Methods We used 14-day full disclosure mobile cardiac telemetry recordings without atrial fibrillation in 8,245 US patients aged 17-103 years to calculate the diagnostic reliability of shorter ambulatory ECG recordings compared to 14-day averages. Results Over 14 days, 1853 patients had ≥500 PACs/day, 410 patients had ≥5000 PACs/day, and 197 patients had ≥10,000 PACs/day; 1640 patients had ≥500 PVCs/day, 354 patients had ≥5,000 PVCs/day and 175 patients had ≥10,000 PVCs/day. After 3 days the estimated daily PAC frequency differed by ≥50% from the 14-day mean in 25% of patients; for PVCs the corresponding duration was 7-days. Ten days of monitoring were needed to estimate PAC and PVC frequency within ±20% of the overall 14-day frequency in 80% of patients. For daily PAC and PVC frequencies ≥10,000 single-day estimation had a specificity of 99.3% (95%CI 99.1-99.5) at a sensitivity of 76.6 (95%CI 70.1-80.4%) for PACs and a 99.6% (95%CI 99.4-99.7%) specificity at 79.4 (95%CI 72.7-85.2) sensitivity for PVCs. After 7 days the sensitivity increased to 88.8% (95%CI 83.6-92.9) for PACs and 86.9% (95%CI 80.9-91.5%) for PVCs. Conclusion While there is substantial daily variability across most PAC and PVC levels, findings of ≥10,000 PACs or PVCs are highly specific and do not need to be confirmed with longer recordings.