Deadly heart attacks are more common on a Monday
The headline is misleading. The actual study proved that the recorded date of admission to hospital in Ireland with ST-segment elevation myocardial infarction was increased on a Sunday and Monday. Increased admissions on a Monday is not that unusual given that people often seek medical attention after the weekend but maybe more surprising is the increase on a Sunday.  https://heart.bmj.com/content/109/Suppl_3/A78