[Isoenzymes after physical loading in ischemic heart disease]

Area of Science:

• Biochemistry
• Cardiology
• Enzymology

Background:

• Ischemic heart disease (IHD) diagnosis and management rely on understanding cardiac stress responses.
• Enzyme and isoenzyme analysis in plasma can provide insights into cardiac function and damage.

Purpose of the Study:

• To investigate the plasma enzyme and isoenzyme patterns in patients with IHD following exercise.
• To identify characteristic changes in enzyme profiles associated with IHD and left ventricular impairment after physical exertion.

Main Methods:

• Plasma samples were collected from IHD patients after a standardized exercise test (bicycle ergometry).
• Enzyme and isoenzyme levels, specifically lactate dehydrogenase (LDH) isoenzymes (LDH-H and LDH-M), were analyzed.
• Results were compared to established "exercise profiles" and "cardiac profiles" and correlated with heart catheterization data.

Main Results:

• Patients with IHD, especially those with severe left ventricular impairment, exhibited distinct changes in plasma enzyme patterns post-exercise.
• Lactate dehydrogenase H (LDH-H) activity and the LDH-H/LDH-M ratio showed a significant increase between 1.5 and 8 hours after exercise.
• The elevated LDH-H/LDH-M ratio normalized approximately 24 hours post-exercise.

Conclusions:

• Exercise-induced changes in plasma enzyme and isoenzyme patterns can serve as indicators of cardiac status in IHD patients.
• The observed alterations in LDH isoenzymes, particularly LDH-H, are linked to the severity of left ventricular impairment in IHD.
• Further investigation correlating these enzymatic changes with comprehensive cardiac assessments like heart catheterization is warranted.