Last Updated on Jan 09, 2020

Cardiovascular Emergencies in Space

Although there are all these changes in the way that the cardiovascular system functions in space, no serious cardiac events in missions have required resuscitation to date, the overall risk of potential cardiac deconditioning developing into a life-threatening illness is approximately 1% per year. Despite this low figure, some documented cases of astronauts presenting disturbances in cardiac rhythm have been observed, such as ventricular tachycardia and prolonged QTc interval after short- and long-duration flights. Ventricular arrhythmias were also reported during the second month aboard the MIR space station, and a loss of left ventricular mass has been seen during the exposure to microgravity. These factors combined could pose extra stress to the cardiovascular system and, in a worst-case scenario, lead to cardiac arrest.

Atrial fibrillation in active astronauts is approximately 5%, which is similar to the general population, although the astronauts belong to a younger age group. This seems to be related to left atrial enlargement and structural changes, as well as an increase in the number of premature atrial contractions observed in space missions.(6)


  1. What is microgravity? - (
  2. Human Pathophysiological Adaptations to the Space Environment - (
  3. Astronaut Lingo: What Is Puffy Head Bird Legs? - (
  4. Recent Findings in Cardiovascular Physiology with Space Travel - (
  5. Spaceflight-Induced Intracranial Hypertension and Visual Impairment - Pathophysiology and Countermeasures - (
  6. Emergencies in Space - (
  7. Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions - (

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