Comparison of optical measurements of critical closing pressure acquired before and during induced ventricular arrhythmia in adults

SIGNIFICANCE: The critical closing pressure (CrCP) of cerebral circulation, as measured by diffuse correlation spectroscopy (DCS), is a promising biomarker of intracranial hypertension. However, CrCP techniques using DCS have not been assessed in gold standard experiments. AIM: CrCP is typically calculated by examining the variation of cerebral blood flow (CBF) during the cardiac cycle (with normal sinus rhythm). We compare this typical CrCP measurement with a gold standard obtained during the drops in arterial blood pressure (ABP) caused by rapid ventricular pacing (RVP) in patients undergoing invasive electrophysiologic procedures. APPROACH: Adults receiving electrophysiology procedures with planned ablation were enrolled for DCS CBF monitoring. CrCP was calculated from CBF and ABP data by three methods: (1) linear extrapolation of data during RVP ([Formula: see text]; the gold standard); (2) linear extrapolation of data during regular heartbeats ([Formula: see text]); and (3) fundamental harmonic Fourier filtering of data during regular heartbeats ([Formula: see text]). RESULTS: CBF monitoring was performed prior to and during 55 episodes of RVP in five adults. [Formula: see text] and [Formula: see text] demonstrated agreement ([Formula: see text] , [Formula: see text] (95%CI, 0.72 to 1.38). Agreement between [Formula: see text] and [Formula: see text] was worse; [Formula: see text] was [Formula: see text] higher than [Formula: see text] (mean ± SD; [Formula: see text]). CONCLUSIONS: Our results suggest that DCS-measured CrCP can be accurately acquired during normal sinus rhythm.