Possibility of the thermographic method for detection
of ischemic myocardium.
Abstract
Thermography (TG) is used as a
contact free method for investigation of the myocardium ischemic injury. In
coronary bypass surgery without artificial blood circulation it is important to
know how cessation of blood supply affects the myocardium. In experiments on
working heart, TG allows monitoring temperature at the desired point of the
epicardium. The aim was to investigate relations between myocardial ischemia
and temperature and to prove that the ischemic tissue and border zones can be
determined by TG. Experiments were performed on mongrel dogs. In the areas of
induced ischemia, ventricular surface thermograms (T) and electrograms (EG)
were recorded. The obtained data showed that temperatures in ischemic area and
border zone of myocardium were different from those in healthy myocardium. A
detailed analysis of T of ischemic area showed that between ischemic and
healthy myocardium a border zone is formed which is very important for
arrhythmia genesis. The border zone is several millimeters wide, and its
temperature is 1C higher than in healthy myocardium. The curve of the dynamics
of temperature measured at all points of the ischemic zone has been created.
Correlation between myocardium temperatures and characteristics of EG of
ischemic zones is shown.
Conclusion- The data show that TG is an appropriate
method for determination of ischemic area and border zone in ventricular
myocardium. TG gives a possibility to evaluate functional status of myocardium
in a contact free way and may be applied for determination of ischemic damage
of myocardium during cardiosurgery.
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