Cardiac arrest vs heart attack: What’s the difference? A cardiac arrest is different than a heart attack. How? Think of it this way: a heart attack is a plumbing problem while a cardiac arrest is an electrical problem. A heart attack occurs due to a blockage in one of your arteries and results in damage to the heart muscle caused by too little blood flow. A cardiac arrest, on the other hand, is the result of abnormal heart rhythm. Cardiac arrest happens when the heart’s electrical system malfunc