Monophasic Action Potential (MAP) is a technique which assesses in vivo cellular potencial using special catheters without the need of using in vitro transmembrane cellular electrodes. We studied the implementation and the results of in vivo endocardial MAPs using electrode-catheters as well as the algorithm used for computed analysis of captured signals. Myocardial repolarization may be affected by several factors that are not detected by the electrocardiogram and are detected by MAP. The algorithm used to analyse the MAP uses morphological and temporal characteristics to assess cellular potencial. Heart transplantation and any cardiomyopathy may alter myocardial fiber structure. We studied 23 patients who were submitted to endomyocardial biopsies, of whom 8 (34.8%) underwent this procedure to evaluate their cardiomyopathy, and 15 (65,2%) in order to evaluate postoperative rejection of the graft. After the biposies we formed 2 groups of 5 patients each; one group was formed of 5 patients with myocardiopathies without active myocarditis, and the other one was formed by 5 patients with and without grad 3A rejection. Our results demonstrated that: 1) the electrode-catheter presented similar results to previous experimental reports; 2) the computed algorithm was efficient and presented similar results to previous experiments; 3) MAP interference due to cardiomyopathy or rejection induces proportional alterations that maintain repolarization morfology; 4) depolarization speed during rejection undergoes a two or three-fold increase.
Action potentials; Myocardium; Myocardial diseases; Heart transplantation; Action potentials
