Cardiac arrhythmias during long-duration spaceflights

Few studies have investigated cardiac arrhythmias during spaceflight. Atrial and ventricular premature contractions, short-duration atrial fibrillation, and non-sustained ventricular tachycardia were reported by previous spaceflight programs. Some of these arrhythmias occurred following extravehicular activity in space. Arrhythmias during spaceflight are related with hypokalemia, microgravity, changes in the autonomic nervous system, and physical stress. Some astronauts have needed radiofrequency catheter ablation for atrial arrhythmias. Future long-duration spaceflights beyond the Earth's orbit may expose astronauts to significant levels of radiation that affect the coronary arteries. Genetic tests for arrhythmias might be added to the present cardiac screening examinations in the future.