<prompt> The predominant isoenzyme of LDH in the cardiac muscle isLDH - 1LDH - 2LDH - 3LDH - 5  <response>: Lactate dehydrogenase LDH is a tetrameric enzyme consisting of two monomer types: H for hea and M for muscle that combine to yield five LDH isozymes: HHH I1, HHHM I2, HHMM I3, HMMM I4, and MMM I5.Isozyme I1 predominates in hea tissue and isozyme I5 in the liver. Thus, when LDH levels rise in blood plasma, the identity of the injured tissue can be inferred from its characteristic pattern of LDH isozymes.In normal plasma LDH-2 is more in concentration than LDH - 1.In myocardial infarction level of LDH - 1 increases and this leads to the altered ratio of LDH.It means LDH - 1 LDH - 2.This altered ratio of the LDH is known as a flipped pattern.Ref: Harper; 30th edition; Page no 69 