Apollo Astronaut Arrhythmias?

Has there been any research why several of the Apollo astronauts and the Apollo 15 astronauts in particular had arrhythmias while in space, James Irwin actually had a heart attack during the return flight I believe.

The arrhythmia answer was meant to be low of potassium. So much so that the astronauts were given a potassium laden drink (and not Tang, or their preferred flavourant) for the remaining missions. Apparently it tasted vile.

James Irvin’s issue would appear to have been symptomatic of an underlying condition, one that caused a number of heart attacks later, and eventually did kill him.

Would not that underlying condition have been screened out during his time as a pilot, aspiring/ trainee astronaut? What kind of tests did they do or could do in those days.

How exactly are space missions on the heart? Are they a, can be bad, usuallly bad or a keep an eye on it but should be fine?

One of the issues in Irwin’s case was that there was nothing to be done for him because when he had his cardiac symptoms, he was in a tin can two days and a hundred thousand miles from the nearest hospital. (Irwin’s episode wasn’t officially classed a heart attack, but at the time the flight surgeon said if he saw a patient on the ground with those symptoms he would treat him for heart attack. That said, the treatment would be to put him in an ICU – 100% oxygen, continual monitoring, rest – all of which he was already getting once they got back to the CSM.)

Another issue on 15 was that the water line in Irwin’s suit got kinked, so he couldn’t hydrate during (I believe) the final lunar EVA. Working on the moon is hard. The suits are bulky, the lessened gravity makes things (like your body) react to force in unexpected ways, the gloves make fine detail work almost impossible, but there’s lots of experiment assembly and similar projects which require it. So in answer to the final question, at least part of the strain it puts on the heart is the same as any really physically demanding job with long hours, limited rest periods, and a dehydrating environment would.


Difficult to know how they could have detected any issue early. We are talking mid 60’s medicine here. No MRI, CT. Basic ECG. They did do very very demanding medical examinations, that drove the astronauts right to the edge of endurance, but unless he had an actual problem during the examination there is a raft of things that would be totally missed. Deke Slayton was detected with atrial fibrillation, and despite being one the original seven, was grounded, and didn’t fly until Apollo Soyuz. So it isn’t as if they weren’t looking.

The demanding nature of the lunar walks is something that is often overlooked. We usually hear how the astronaut only weighted one sixth as much in lunar gravity. What we don’t hear is that their inertial mass was the same, so with the suit and backpack they still had to manage to control a very large mass as they moved. Further, the significant stiffness of the pressure suit makes all movements require a lot of effort. Making the gloves was really difficult, and there were astronauts that finished the lunar walk with fingers black from bruising. There were very good reasons they were wired up to the extent they were. The flight surgeon sat in mission control, and managed his wetware as much as the other guys managed the hardware.

It was the stress of keeping the conspiracy quiet, of course.

Did they have anti arrythmic drugs in those days?