CARDIAC MARKERS IN MI, AMI and Myocardial Injury - || MedicScientist :: Total Health Portal || Quality Generic Medicines ||

CARDIAC MARKERS IN MI

Serum proteins released in blood from necrotic heart muscles after AMI are called serum markers .

Creatinine phosphokinase (CK)

CK increased in :

MB Isoenzyme of CK :

Some Properties of Serum Markers of Myocardial Injury

Marker Time to Appear ,Time to Peak and Time Return to Normal
Myoglobin 0.5-2h Marker Time to Appear 5-12h Time to Peak 18-30h Return to Normal
CPK-Isoforms 1-4h Marker Time to Appear 4-8h Time to Peak 12-24h Return to Normal
CPK-MB 3-8h Marker Time to Appear 9-30h Time to Peak 2-3d Return to Normal
CPK-Total 3-8h Marker Time to Appear 10-36h Time to Peak 3-4d Return to Normal
Cardiac Troponins 3-6h Marker Time to Appear 10-24h Time to Peak 5-15d Return to Normal
LDH 8-18 Marker Time to Appear 2-3d Time to Peak 6-10d Return to Normal

Ratio of CKMB :

CK > 2.5 su _g~sts MI (but not diagnostic).
Requires series of measurements obtained over 1S^t 24 hrs.
Skeletal muscle CKMB pattern a Plateau.
Myocardial form CKMB is CKMB2.
KMB2 : CKMB1 ratio of > 1. 5 (diagnostic for AMI 4-6 Iirs after coronary occlusion.

Cardiac Troponins

C TnT and C TnI.
Cardiac specific troponin T and I are biochemical markers of choice.
TnI – remains elevated upto 10 days.
C TnT may be elevated for 10 – 14 days.
Early recanalization of coronary occlusion by mechanical means or drugs results in early peaking and higher peaks.
In microinfarctions CKMB normal but cTnT or I elevated.

Myoglobin

Rises few hours after AMI and comes to normal within 24 hours.
Elevation of LDH and isoenzymes is upto 48 hrs Not used now.
CKMB may be useful only for repeat episodes in 2 ~eeks otherwise-only cTnI and / or cTnT may be do~e.
Ideally serum cardiac markers should be measured at time of admission, 6-9 hrs after admission and 1224 hrs after admission.

Non specific lab tests