“Flipping effect” is ?
Ref. API Textbook of Medicine. Pg. 798
 
Lactate dehydrogenase, tetrameric enzyme with 4 subunits,

4 Subunits with 2 isoforms - H isoform (Heart) & M isoform (Muscle)
Heart & RBCs - LDH-1 (4H);
Reticuloendothelial system - LDH-2 (3H1M)
Lungs - LDH-3 (2H2M)
Kidneys, placenta, & pancreas - LDH-4 (1H3M)
Liver & striated muscle - LDH-5 (4M)

Flipping effect

Usually LDH 2 in predominant in serum & LDH 1 is predominant in heart
Higher levels of LDH 1 than LDH 2 (Flipped pattern) is suggestive of myocardial infarction
LDH 1> LDH 2
LDH2>LDH1
LDH 2> LDH 3
LDH 3>LDH 2