A simultaneous multichannel monophasic action potential electrode array for in vivo epicardial repolarization mapping

2001 ◽  
Vol 48 (3) ◽  
pp. 345-353 ◽  
Author(s):  
A.V. Sahakian ◽  
M.-S.L. Peterson ◽  
S. Shkurovich ◽  
M. Hamer ◽  
T. Votapka ◽  
...  
Keyword(s):  
Action Potential ◽  
Electrode Array ◽  
Monophasic Action Potential ◽  
Potential Electrode

Rate-dependent differences in dog epi- and endocardial monophasic action potential configuration in vivo

1991 ◽  
Vol 261 (5) ◽  
pp. H1387-H1391 ◽  
Author(s):  
P. M. Tande ◽  
E. Mortensen ◽  
H. Refsum
Keyword(s):  
Action Potential ◽  
Phase 1 ◽  
Outward Current ◽  
Ventricular Repolarization ◽  
Monophasic Action Potential ◽  
Transient Outward Current ◽  
Phase 2 ◽  
Lower Phase

A transient outward current (Ito), long considered to be a unique feature of Purkinje fiber tissue, has recently been demonstrated in dog ventricular tissue in vitro and most prominently in the epicardium. To investigate its possible contribution to ventricular repolarization in vivo, we recorded right ventricular endocardial and epicardial monophasic action potentials (MAP) simultaneously in pentobarbital-anesthetized open-chest dogs. Epicardial MAP had lower phase 1 than phase 2 amplitude at both spontaneous heart rate and paced cycle length of 300 and 400 ms. This "spike-and-dome" morphology of the epicardial MAP, possibly attributable to Ito, progressively disappeared at shorter extrastimulus intervals. In endocardium the phase 1 amplitude was always higher or equal to phase 2 amplitude and was not affected by shorter extrastimulus intervals. The action potential duration (APD) was shorter in epicardium than in endocardium. Both endocardial and epicardial APD shortened as the premature intervals were reduced, but the shortening was not parallel. The restitution curves converged so that, at the shortest intervals (160 ms), there were no longer any significant differences in APD between endocardium and epicardium. This study indicates that Ito contributes to ventricular repolarization in vivo, and most prominently in the epicardium. Unequal shortening of APD between endocardium and epicardium after progressively shorter diastolic intervals may thus partly result from uneven distribution of Ito across the ventricular wall.

scholarly journals New insights into application of cardiac monophasic action potential

2010 ◽  
pp. 645-650
Author(s):  
S-G Yang ◽  
O Kittnar
Keyword(s):  
Action Potential ◽  
Time Course ◽  
Cardiac Tissue ◽  
Femoral Vein ◽  
Myocardial Cell ◽  
Monophasic Action Potential ◽  
Seldinger Technique ◽  
Accurate Information ◽  
Length Changes

Monophasic action potential (MAP) recording plays an important role in a more direct view of human myocardial electrophysiology under both physiological and pathological conditions. The procedure of MAP measuring can be simply performed using the Seldinger technique, when MAP catheter is inserted through femoral vein into the right ventricle or through femoral artery to the left ventricle. The MAP method represents a very useful tool for electrophysiological research in cardiology. Its crucial importance is based upon the fact that it enables the study of the action potential (AP) of myocardial cell in vivo and, therefore, the study of the dynamic relation of this potential with all the organism variables. This can be particularly helpful in the case of arrhythmias. There are no doubts that physiological MAP recording accuracy is almost the same as transmembrane AP as was recently confirmed by anisotropic bidomain model of the cardiac tissue. MAP recording devices provide precise information not only on the local activation time but also on the entire local repolarization time course. Although the MAP does not reflect the absolute amplitude or upstroke velocity of transmembrane APs, it delivers highly accurate information on AP duration and configuration, including early afterdepolarizations as well as relative changes in transmembrane diastolic and systolic potential changes. Based on available data, the MAP probably reflects the transmembrane voltage of cells within a few millimeters of the exploring electrode. Thus MAP recordings offer the opportunity to study a variety of electrophysiological phenomena in the in situ heart (including effects of cycle length changes and antiarrhythmic drugs on AP duration).

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