Computer magnitocardiography in myocardial reserve assessment

The purpose of the present work was to disclose the number of the qualitative and quantitative magnetocardiographic (MCG) parameters for evaluation of the effects the breathing and stress tests exerted on the functional myocardial reserve in 30 normal and 10 subjects with old myocardial infarction. Computerized magnetocardiography was fulfilled before (resting subjects), during and after (resting subjects) the Stange test and Valsalva maneuver (7 normal subjects), before and after the standartized knee-bending exercise. The next trends were revealed: an increase in «curvature» of the magnetic field isolines distribution on the magnetic field maps (in the area of the right atrium projection) and the plane summary current of the myocardium of the atrial system in the frontal plane during the breathing tests, related to an increase in the right atrium hydrostatic pressure and hemodynamic reserve volume; predominance of the right atrium and the right ventricle current components in the summary currents of the atria and the ventricles; an increase in a magnetocardiosignal amplitude on the ST segment and the T wave amplitude of the «basic» PQRST magnetocardiocycle after the knee-bending exercise in contractile reserve-positive subjects, as compared with the baseline measurements at rest and the reverse trend in contractile reserve-negative subjects, up to the negative T wave formation. Our results showed that CMCG method allows to evaluate functional hemodynamic and contractile myocardial reserves in a new fashion from the electromagnetic viewpoint by analyzing CMCG parameters, describing interatrial, interventricular and atrio-ventricular interactions.