<prompt> Which is the BEST diagnostic enzymatic essay to be done within 4 hours following an acute MI?MB isoenzyme of CKReagin isoenzymeLDH4LDH1  <response>: CREATINE KINASE: INCREASED IN: Muscle damage AMI, myocarditis, muscular dystrophy, muscle trauma , aftermath of surgery, brain infarction, defibrillation, cardiac catheterization and surgery, rhabdomyolysis, polymyositis, hypothyroidism. CPK Isoenzymes: Increased CK MB is seen in: Normal 6, hea origin increased in AMI begins in 2-12 h, peaks at 12-40 h, returns to normal in 24-72 h; troponin is marker of choice for AMI; pericarditis with myocarditis, rhabdomyolysis, crush injury, Duchenne muscular dystrophy, polymyositis, malignant hypehermia, cardiac surgery. MM: Normal 94-100, skeletal muscle origin increased in crush injury, malignant hypehermia, seizures, IM injections BB: Normal 0, brain origin brain injury CVA, trauma, metastatic neoplasms eg, prostate, malignant hypehermia, colonic infarction. Ref: Gomella L.G., Haist S.A. 2007. Chapter 4. Laboratory Diagnosis: Chemistry, Immunology, Serology. In L.G. Gomella, S.A. Haist Eds,Clinicians Pocket Reference: The Scut Monkey, 11e. 