Prefrontal and muscle oxygenation responses to supraventricular tachycardia

Abstract

Supraventricular tachycardia (SVT) causes hypotension and cerebral hypoperfusion leading to syncope at times. The cerebral and peripheral vascular systems probably operate to maintain cerebral oxygenation against SVT‐induced hypoperfusion. However, time courses of cerebral and peripheral oxygenation responses to SVT has not been fully understood. The aim of this study was to examine the time course and relationship between cerebral and peripheral oxygenation responses and SVT‐induced hypotension. Prefrontal and forearm tissue oxygen index (TOI) and normalized tissue hemoglobin index (nTHI) were collected by near‐infrared spectroscopy (NIRS) during electrophysiological study (EPS) in 14 patients (55 ± 4 years old, 9 men) with SVT. AP decreased during 2–20 s of SVT. The prefrontal TOI and nTHI began to decrease (P < 0.05) transiently at 6 s of SVT and then returned to the baseline level from 14 s. The initial decrease of prefrontal TOI appears to occur when hypotension was over approximately 20 mmHg. In contrast, the forearm TOI and nTHI decreased continuously from 11 s (P < 0.05). The AP and prefrontal NIRS responses suggest that SVT‐induced great hypotension (>20 mmHg) caused the transient reduction of cerebral oxygenation and blood volume, which may be followed by a recovering process owing to cerebral vasodilatation. The continuous reductions of forearm TOI and nTHI during SVT suggest restriction of muscle blood flow by vasoconstriction, which may contribute to redistribution of the blood to the brain.Support or Funding InformationThis research is supported by Automotive and Medical Concert Consortium (AMECC).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.