Before oxygen came into being, the oldest growing and dividing microbe appeared on Earth nearly 3.8 billion years ago. Taking Earth's age as nearly 4.6 Billion Years, instead of 13.7 from Big Bang, unicellular life appeared nearly 3.8 ago. This percentage is 3.8/4.6 X 100 = 82.6%, of time has life existed on earth.
Hypomagnesemia is a condition of low magnesium levels in the body and because magnesium acts as an active cardiovascular electrolyte, its deficiency leads to cardiac complications such as dysrhythmias.
People who suffer from myocardial infarction are often treated for hypomagnesemia to improve their cardiac conduction, however, hypomagnesemia can also develop in chronic alcoholics.
The other reasons that could lead to the condition faced by Robert Stevens can be hypokalaemia however, as he is also chronic alcoholic hypomagnesemia is the main cause.