There is a difference between cardiac arrest and a heart attack. A hear attack may result in cardiac arrest, but not necessarily. A heart attack, or myocardial infarction, is a blockage of a blood vessel in the heart and part of the heart muscle begins to die. If enough of it dies, cardiac arrest can result. Cardiac arrest can also result from trauma, such as a fight.

The article does not state the cause of Officer Nesbitt's cardiac arrest. It may have been trauma from the fight itself, or it may have been the strain on an already weakened heart, in other words bad timing. It is not uncommon for a person who has been seen as previously healthy to drop dead from cardiac arrest as a result of a heart attack.