Introduction

Presence of low voltage areas (LVA) mirrors AF progression and is associated with an impaired rhythm outcome. P-wave indices can predict LVA, however accuracy is depending on myocardial mass. The aim of current analysis was to investigate the association between the novel P-Wave Area Index (PWAi) and the presence of LVA.

Methods

Patients undergoing first AF ablation were included into analyses. LVA were determined using high-density maps and defined as <0.5 mV. All patients underwent CMR imaging (Ingenia 1.5T Philips) and received 12 lead ecg in sinus rhythm before intervention. CMR data (left atrial area) and the P Wave area in Leads I and II were measured in all patients. Afterwards the P Wave area was indexed for LA area to create the PWAi.   

Results

A total of 264 consecutive patients were included in the analysis (65 years, 41% females, 57% persistent AF, 30.6% LVAs). Of all analyzed P-Wave indices, P Wave Area in lead II was found to effectively identify LVA (AUC: 0.813, p<0.001). In patients with LVA, the newly introduced PWAi below 0.4781 msec*mV*m²/cm² identified patients with LVA with an accuracy of 81% (81% sensitivity, 81% specificity, 65% pos. predictive value and 91% neg. predictive value) and yielded the highest Odds ratio among analyzed parameters (OR: 20.578, p<0.001; AUC: 0.860)

Conclusion:

The PWAi is a highly significant tool to identify LVA before AF ablation. These findings help to further individualize AF treatment. 

Figure 1: ROC Curves of ECG Indices and PWAi.

AUC for 1) terminal negative proportion of the P wave integral in Lead V1 (PTFV1): 0.561 (95%CI [0.431 – 0.627]; p<0.001); 2) for p wave area in lead I (PWA (I)): 0.646 (95%CI [0.571 – 0.721]; p<0.001), 3. for p wave area in lead I (PWA (II)): 0.813 (95%CI [0.758 – 0.868]; p<0.001), 4. P-Wave Area Index (PWAi): 0.860 (95%CI [0.812 – 0.907]; p<0.001).