Abstract 18759: Reliability and Accuracy of Non-Invasive versus Invasive Blood Pressure Monitoring During Atrial Fibrillation Ablation

Introduction Patients with atrial fibrillation (AF) have multiple confounders that could affect the reliability of non-invasive blood pressure (NIBP). We sought to investigate if AF and paced rhythms (PR) modify the reliability of NIBP and accuracy against an invasive blood pressure (IBP) reference, as compared to sinus rhythm (SR), and impact NIBP validity for procedural monitoring. Hypothesis Changes in heart rhythm between AF, SR and PR, within a patient would not alter the reliability and accuracy of NIBP. Methods We conducted an observational study in patients undergoing an AF ablation procedure under general anesthesia with paired IBP, NIBP, and heart rhythm measurements available. Results We evaluated 91 patients ( Table 1 ) with 1,179 usable NIBP vs. IBP pairs; 547 (46.4%) during SR, 376 during AF (31.9%), and 256 (21.7%) during PR. In the entire sample, the average difference (standard error) between systolic NIBP and IBP was 2.9 (1.8) mmHg (P=0.10 against H0=0) with a within-subject standard deviation (SD) for the difference of 11.6 mmHg and intraclass correlation coefficient of 0.76 ( Fig. 1 ). Systolic NIBP was higher on average vs. IBP when in SR (6.2 [1.1] mmHg; P<0.001), but not when in AF (1.5 [2.6] mmHg; P=0.55) or in PR (-2.0 [3.3] mmHg; P=0.54). However, the within-patient SD of the difference was high in SR, AF, and PR (SD 10.5, 12.9, and 11.9 mmHg, respectively). Results were similar for diastolic and mean NIBP vs. IBP. Conclusion AF or PR, as compared to SR, did not materially change the reliability and accuracy of NIBP vs. IBP. However, the high within-patient variation in systolic NIBP versus IBP raises concerns on the validity of NIBP for systolic blood pressure monitoring.