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The clinical management of arrhythmias is difficult.
Despite remarkable progress in understanding the basic anatomy and physiology of many
important cardiac arrhythmias, clinical guidelines for management are poorly evolved.
There are several explanations for this situation. The therapeutic armamentarium comprises
a large range of antiarrhythmic agents which traditionally have been grouped into the
Vaughan Williams classification on the basis of their cellular electrophysiological
actions1,2. Many of the currently available
antiarrhythmic drugs are relatively old. Some would not pass present day stringent
standards in respect of efficacy and their unwanted effect profile. On the other hand,
cardiac arrhythmias have proved difficult to classify and define. Even to this day, it is
only those with a particular interest in arrhythmias that are likely to subdivide so
called supraventricular tachycardias into those due to accessory pathways, those due to AV
nodal reentry and those due to atrial reentrant or ectopic generators. Such sophistication
in diagnosis is not pedantry3. Specific individual
diagnoses such as these reflect fundamentally different arrhythmias each with their own
unique electrophysiological mechanism, anatomic determinants and pathological
associations.
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