Circadian variation of cardiac troponin

Acute myocardial infarction (AMI) is defined by an increase and/or decrease in
the concentration of cardiac troponin, with at least one value above the 99th
percentile value of the reference population together with evidence of
ischemia. An objective tool to determine the magnitude of the cardiac troponin
change is the use of reference change values (RCV). The basis for this tool is
that, for a change to be significant, the difference in serial results must be
greater than the inherent variation in two test results. The inherent variation
of a laboratory test result is composed of analytical and within-subject
biological variation. The assessment of these variance components in the case
of cardiac troponin testing is usually conducted with individuals without any
evidence of active cardiovascular disease. These calculations cannot be done
with AMI patients because AMI is a dynamic disease with changing cardiac
troponin concentrations. However, an important requirement to use RCVs is that
the concentrations of cardiac troponins fluctuate randomly around a homeostatic
set point in cardio-healthy individuals. Verification of this important
condition has never been performed, and violation of this condition would
preclude the use of RCV*s in clinical practice.

To assess the circadian variation of cardiac troponins in individuals without
any evidence of active cardiovascular disease.

Interventional study consisting of one wake- and sleep cycle with a total
duration of 26 hours.

There are no direct benefits for the participating subjects. The risks
associated with the proposed study are low. At the insertion site of the
intravenous catheter, a hematoma could occur.