<prompt> The predominant isozyme of LDH in cardiac muscle is:LD-1LD-2LD-3LD-5  <response>: LD-1 is the predominant isoenzyme of LDH in cardiac muscle. Ref: Harpers Principles of Internal Medicine, 26th Edition, Page 57; Textbook of Biochemistry By Vasudevan, 5th Edition, Page 53 