PO-710-08 DAILY PVC VARIABILITY AFFECTS 2017 AHA/ACC/HRS EXPERT CONSENSUS CUTOFF

Abstract

In the setting of PVC-induced cardiomyopathy, a general cutoff of >15% PVCs has been suggested by the 2017 AHA/ACC/HRS Expert Consensus guidelines when considering PVC ablation. However, the influence of daily PVC variability on this >15% threshold has yet to be established. To investigate daily PVC variability via 14-day rhythm monitoring in a large patient cohort. Retrospective analysis was performed on 325 anonymized 14 day ZIO® (iRhythm) datasets (4,550 patient days) with ≥1 day of >15% PVCs. Daily PVC burden ranged from 0 to 48%, with a median daily PVC percentage (14.1%; Q1/3: 9.9%/20.2%) significantly different from the lowest (7.8%, Q1/3: 3.4%/13.0%) or highest (21.6%; Q1/2: 18.2%/28.5%) daily PVC percentage (p<0.001 for both). Bigeminy days (defined here as ≥40% PVCs) were rare (68 of 4,550 days) and present in only 16 patients. Intra-patient daily PVCs were highly variable, with a 2.7 fold (Q1/Q3: 1.8/6.5) variance between the maximum and minimum PVC day and up to a >20,000 fold variance observed. Population analysis demonstrated a bimodal distribution with two distinct subgroups of PVC patterns in 52% of patients: “low frequency/low PVC” (only ≤3 of 14 days with >15% PVCs/on those days n=17.9% (IQR 2.5%) mean PVCs) and “high frequency/high PVC” (all 14 days with >15% PVCs/on those days n=28.5% (IQR 10.1%) mean PVCs, p<0.001). 83% of patients had ≥1 day of <15% PVCs, 33% had ≥1 day of <5% PVCs, and 15% had ≥1 day of <1% PVCs, indicating that a 24h monitor would have failed to identify patients with >15% PVCs or misclassified patients as unlikely to suffer from a significant PVC burden. The 2017 Expert Consensus PVC cut-off of 15% was more selective, identifying only 53.6% of patients that qualified for ablation based on the 2014 EHRA/HRS/APHRS Expert Consensus cutoff of ≥10,000 PVCs/24h. Daily PVC burden in a larger patient cohort is more variable than expected. Days of bigeminy are rare and clustered in relatively few patients. Newly identified patterns such as “high frequency/high PVC” and “low frequency/low PVC” may exist even among those meeting 2017 Expert Consensus PVC cutoffs. A threshold of >15% PVCs is considerably more selective than ≥10,000 PVCs/day. These observations all have potential to affect patient selection and response to PVC suppression/ablation.