A heart attack is a plumbing problem. Sudden Cardiac Arrest is an electrical problem. To explain further, a heart attack is typically caused by a blockage in a blood vessel to the heart muscle. This can permanently damage part of the heart. SCA is an electrical malfunction that disrupts the timing and order of the pumping action. A heart attack can lead to cardiac arrest. In either case, blood stops flowing to the body and brain, and that's trouble.