Pharmacological modification of the dispersion of repolarization in the heart: importance of the M cells.
Several in vitro and in vivo investigations have provided data supporting the existence of M cells in the deep subepicardial layers of the ventricles in a number of species. Characterized by unique electrophysiological and pharmacological features, this population of cells is regarded to have a significant role in creating dispersion of repolarization in the ventricular wall and thus contribute importantly to arrhythmogenesis, in particular to intramural reentry and triggered activity. Focusing on M cells, the authors summarize recent findings and concepts concerning the pharmacological heterogeneity of different cell and tissue types found within the ventricles and explore how these differences may contribute to electrocardiographic manifestations. On the basis of literary data and of their own results they conclude that studying the electrical and pharmacological inhomogeneity within the ventricular wall may provide a better understanding of the pathophysiological processes that give rise to cardiac rhythm disturbances and the mechanisms by which antiarrhythmic agents act to suppress and in some cases aggravate arrhythmias.
Baláti
B
B
Department of Pharmacology and Pharmacotherapy, Albert Szent-Györgyi Medical University, Szeged, Hungary.
Varró
A
A
Papp
J G
JG
D001145:Arrhythmias, Cardiac / Q000209:etiology; D002317:Cardiovascular Agents / Q000494:pharmacology; D004594:Electrophysiology; D006352:Heart Ventricles / Q000166:cytology*; D066298:In Vitro Techniques; D017136:Ion Transport / Q000502:physiology*; D016276:Ventricular Function
D002317:Cardiovascular Agents