The National Center for Cardiovascular Research in Madrid analyzed data from over 800 patients who had been treated for heart attacks between 2003 and 2009. They focused their attention on two important enzymes that are released into the bloodstream when the heart muscle is damaged, creatine kinase and troponin.
What they found was that those who suffered heart attacks between the hours of 6 A.M. and noon had higher levels of the two enzymes, and therefore suffered more extensive damage to the heart muscle.
This is the very first study to ever show that timing during the day is an important factor in the extent of damage to the heart. Information such as this will be useful to ER physicians, amongst other doctors, when evaluating a patient presenting to their emergency room. It always raises urgency issues when contemplating who to send to the catheterization lab no matter the time of day, but knowing those who experience a heart attack in the morning are more prone to extensive damage will rightly escalate the urgency for optimal patient care.