Clinical relevance of cardiac arrhythmias generated by afterdepolarizations. Role of M cells in the generation of U waves, triggered activity and torsade de pointes

J Am Coll Cardiol. 1994 Jan;23(1):259-77. doi: 10.1016/0735-1097(94)90529-0.


Recent findings point to an important heterogeneity in the electrical behavior of cells spanning the ventricular wall as well as important differences in the response of the various cell types to cardioactive drugs and pathophysiologic states. These observations have permitted a fine tuning and, in some cases, a reevaluation of basic concepts of arrhythmia mechanisms. This brief review examines the implications of some of these new findings within the scope of what is already known about early and delayed afterdepolarizations and triggered activity and discusses the possible relevance of these mechanisms to clinical arrhythmias.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Anti-Arrhythmia Agents / pharmacology
  • Arrhythmias, Cardiac / physiopathology*
  • Electrocardiography*
  • Heart Conduction System / drug effects
  • Heart Conduction System / physiopathology*
  • Humans
  • Long QT Syndrome / physiopathology
  • Myocardium / cytology*
  • Purkinje Fibers / physiopathology
  • Torsades de Pointes / physiopathology*


  • Anti-Arrhythmia Agents