A method of assessing cardiac ischemia in a subject to provide a measure of
cardiac or cardiovascular health in that subject is described herein. The
method comprises the steps of: (a) collecting a first RR-interval data set
from the subject during a stage of gradually increasing heart rate (e.g.,
a stage of gradually increasing exercise load); (b) collecting a second
RR-interval data set from the subject during a stage of gradually
decreasing heart rate (e.g., a stage of gradually decreasing exercise
load); (c) comparing the first RR-interval data set to the second
RR-interval data set to determine the difference between the data sets;
and (d) generating from the comparison of step (c) a measure of cardiac
ischemia during exercise in the subject. A greater difference between the
first and second data sets indicates greater cardiac ischemia and lesser
cardiac or cardiovascular health in the subject. Heart rate is gradually
increased and gradually decreased in response to actual heart rate date
collected from concurrent monitoring of the subject. The data sets are
collected in such a manner that they reflect almost exclusively the
conduction in the heart muscle and minimize the effect on the data sets of
rapid transients due to autonomic nervous system and hormonal control.
