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

Abstract

.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 (; the gold standard); (2) linear extrapolation of data during regular heartbeats (); and (3) fundamental harmonic Fourier filtering of data during regular heartbeats ().Results: CBF monitoring was performed prior to and during 55 episodes of RVP in five adults. and demonstrated agreement (, (95%CI, 0.72 to 1.38). Agreement between and was worse; was higher than (mean ± SD; ).Conclusions: Our results suggest that DCS-measured CrCP can be accurately acquired during normal sinus rhythm.