Monophasic Action Potentials:

Abstract

Monophasic action potential (MAP) recordings reproduce the repolarization time course of intracellular action potentials with high accuracy and provide precise information on the local activation time. With the advantage of in vivo application and the development of the safer and simpler contact catheter technique, MAP recording has become the method of choice for evaluating myocardial repolarization changes. This review aims to provide information on practical application of MAP recording in the clinical setting. MAPs can easily be recorded from the endocardium with the contact catheter technique in the electrophysiology laboratory and from the epicardium with electrode probes during open heart surgery. The technical aspects are described in detail. The rate dependence of myocardial excitability and repolarization and the effect of antiarrhythmic drugs on MAP duration and effective refractory period are thoroughly reviewed. The use of MAPs in detecting myocardial ischemia, in studying early afterdepolarization and triggered arrhythmias, in measuring dispersion of repolarization, in identifying intracardiac conduction and the development of the T wave, and in verifying the arrhythmogenic effect of mechanoelectric feedback are presented. Computerized automatic analysis of MAPs and the limitations of the MAP technique are also discussed.

Monophasic Action Potentials of the Right Atrium in Patients With Paroxysmal Atrial Fibrillation.

“…[16][17][18] Abnormally fractionated RA electrograms during sinus rhythm are characteristic in patients with PAF. 19 MAPs can be easily recorded from the endocardium using the contact catheter technique and Olsson et al have shown that such recordings accurately reproduce the repolarization time course of intracellular action potentials, 7,20 thus allowing basic cellular events to be studied in the human heart. We have confirmed that MAPs from the RA and RV provided extremely useful clinical and electrophysiological data in various diseases, 9,21,22 and Franz et al identified a very close correlation between action potential duration (MAPD) and ERP in the human myocardium.…”