Electrophysiology and pharmacology of cardiac arrhythmias. III. The causes and treatment of cardiac arrhythmias. Part B

Studies on the electrophysiologic mechanisms responsible for disturbances of cardiac rate, rhythm, and conduction, and studies on the actions and mechanisms of action of antiarrhythmic and other drugs, permit the development of an apparently reasonable approach to treatment of cardiac arrhythmias. Some of the rules derived from an appreciation of cardiac electrophysiology are generally applicable. Others appear to require further testing. There are many discrepancies between what can be predicted or expected and what happens; these discrepancies result from many factors. It is likely that cardiac disease in humans has effects on the electrical activity of cardiac cells which have not been reproduced in the laboratory. It is likely, also, that disease modifies the response of cardiac cells to drugs in ways that have not yet been discovered. Nevertheless, some progress has been made and further experiment and thought may provide both better understanding and new and better therapeutic agents.