New insights into application of cardiac monophasic action potential

Monophasic action potential (MAP) recording plays an importantrole in a more direct view of human myocardial electrophysiologyunder both physiological and pathological conditions. Theprocedure of MAP measuring can be simply performed using theSeldinger technique, when MAP catheter is inserted throughfemoral vein into the right ventricle or through femoral artery tothe left ventricle. The MAP method represents a very useful toolfor electrophysiological research in cardiology. Its crucialimportance is based upon the fact that it enables the study of theaction potential (AP) of myocardial cell in vivo and, therefore, thestudy of the dynamic relation of this potential with all theorganism variables. This can be particularly helpful in the case ofarrhythmias. There are no doubts that physiological MAPrecording accuracy is almost the same as transmembrane AP aswas recently confirmed by anisotropic bidomain model of thecardiac tissue. MAP recording devices provide precise informationnot only on the local activation time but also on the entire localrepolarization time course. Although the MAP does not reflect theabsolute amplitude or upstroke velocity of transmembrane APs, itdelivers highly accurate information on AP duration andconfiguration, including early afterdepolarizations as well asrelative changes in transmembrane diastolic and systolic potentialchanges. Based on available data, the MAP probably reflects thetransmembrane voltage of cells within a few millimeters of theexploring electrode. Thus MAP recordings offer the opportunity tostudy a variety of electrophysiological phenomena in the in situheart (including effects of cycle length changes andantiarrhythmic drugs on AP duration).