Objective of the study is to clarify humanin-like peptide concentration in myocard tissue and in blood and to study if its concentration level is related to early complication occurrence and frequency after cardiac operation.

Hypothesis of the study is that previously described elements are related to each other.

Data collection: Historical medical and preoperative data, operation data (type of operation performed and its details), detailed postoperative course (occurrence of complications).

Specimen collection:

• Tissue sample is taken during the operation from the right atrial appendage of the heart and the sample is frozen at -80 C.
• Blood samples are taken just before the operation, one hour after aortic cross-clamp removal and the next morning after the operation. Samples are processed and blood plasma is frozen at -80 C.

Inclusion Criteria:

• Age at least 18 years
• Ischemic heart disease in medical history
• Planned on-pump coronary artery bypass graft (CABG) operation
• Signed informed consent by patient

Exclusion Criteria:

• Age <18 years
• Planned isolate valve or aortic operation
• Patient is in another study with an intervention
• Absence of signed informed consent

All adult patients who have a history of ischemic heart disease and who are going to have an elective on-pump CABG operation.