Dysrhythmias in laypersons during centrifuge-simulated suborbital spaceflight

Rahul Suresh, Rebecca S. Blue, Charles H. Mathers, Tarah L. Castleberry, James M. Vanderploeg

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

INTRODUCTION: There are limited data on cardiac dysrhythmias in laypersons during hypergravity exposure. We report layperson electrocardiograph (ECG) findings and tolerance of dysrhythmias during centrifuge-simulated suborbital spaceflight. METHODS: Volunteers participated in varied-length centrifuge training programs of 2-7 centrifuge runs over 0.5-2 d, culminating in two simulated suborbital spaceflights of combined +Gz and +Gx (peak +4.0 Gz, +6.0 Gx, duration = s). Monitors recorded pre- and post-run mean arterial blood pressure (MAP), 6-s average heart rate (HR) collected at prespecified points during exposures, documented dysrhythmias observed on continuous 3-lead ECG, self-reported symptoms, and objective signs of intolerance on real-time video monitoring. RESULTS: Participating in the study were 148 subjects (43 women). Documented dysrhythmias included sinus pause (N = 5), couplet premature ventricular contractions (N = 4), bigeminy (N = 3), accelerated idioventricular rhythm (N = 1), and relative bradycardia (RB, defined as a transient HR drop of > .20 bpm; N = 63). None were associated with subjective symptoms or objective signs of acceleration intolerance. Episodes of RB occurred only during +Gx exposures. Subjects had a higher post-run vs. pre-run MAP after all exposures, but demonstrated no difference in pre- and post-run HR. RB was more common in men, younger individuals, and subjects experiencing more centrifuge runs. DISCUSSION: Dysrhythmias in laypersons undergoing simulated suborbital spaceflight were well tolerated, though RB was frequently noted during short-duration +Gx exposure. No subjects demonstrated associated symptoms or objective hemodynamic sequelae from these events. Even so, heightened caution remains warranted when monitoring dysrhythmias in laypersons with significant cardiopulmonary disease or taking medications that modulate cardiac conduction.

Original languageEnglish (US)
Pages (from-to)1008-1015
Number of pages8
JournalAerospace Medicine and Human Performance
Volume88
Issue number11
DOIs
StatePublished - Nov 1 2017
Externally publishedYes

Keywords

  • +G
  • +G
  • Bradycardia
  • Commercial spaceflight
  • Dysrhythmia
  • Electrocardiogram
  • Tolerance
  • Vagal

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Public Health, Environmental and Occupational Health

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