Mechanisms of paroxysmal supraventricular tachycardia

Paroxysmal supraventricular tachycardia can be classified into the following specific mechanisms in man: (1) atrioventricular nodal reentrance that can be subclassified into 'dual atrioventricular nodal pathways', and 'reflection'; (2) sinus node reentrance; (3) atrial reentrance; (4) possibly, His bundle reentrance; and (5) ectopic firing. Delineation of the mechanisms of PSVT may have therapeutic implications. Drugs such as digitalis, propranolol, procainamide, and quinidine having different effects on different tissues could prevent or abolish one type of PSVT and might precipitate or potentiate other types of PSVT. In addition, the same antiarrhythmic agent beneficial for one patient could be deleterious for other patients, even with the same type of PSVT. Electrophysiological studies may improve patient management.