Simplify the following text for a Grade 5 native English-speaking person.
Original: Cardiac muscle is similar to skeletal muscle in both composition and action , being made up of myofibrils of sarcomeres , but anatomically different in that the muscle fibers are typically branched like a tree and connect to other cardiac muscle fibers through intercalcated discs , and form the appearance of a syncytium .
Simplified: The Cardiac muscle is the muscle in the heart .