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I note that this ECG after collapse showed a prolonged QTc. This occurs in hypomagnesia and treatment of any arrythmia with magnesium may be life saving. The magnesium status is best obtained from red cells rather than serum. Because of the western populations poor diet with an excess of dairy and lack of vegetables it is common for people to have a high intake of calcium and poor intake of magnesium. Young sportsmen who take whey supplements are at particular risk. In all cases of sudden collapse in healthy young people it would be wise to assess their magnesium and omega 3 status before blaming it on their genes.Both magnesium and omega 3 have an anti-arrythmic effect.