The hemodynamic consequences of supraventricular tachyarrhythmias may be trivial or serious depending on the presence and severity or absence of underlying heart disease and on the duration of the tachyarrhythmia. It is important to recognize and emphasize that the treatment of supraventricular tachyarrhythmias must be tailored to the individual setting in which it occurs, and that full understanding of the clinical circumstances in which these tachyarrhythmias develop is essential for optimal therapy in individual patients. Treatment of these tachyarrhythmias includes treatment of the underlying disease. Precipitating factors, such as use of alcohol, tobacco, and coffee, also should be eliminated when feasible.

We wish to emphasize that there is no "cookbook" approach to the management of supraventricular tachyarrhythmias. Moreover, no one should use any antiarrhythmic drug without understanding its pharmacologic and physiologic mechanisms.

PAROXYSMAL ATRIAL TACHYCARDIA AND PAROXYSMAL ATRIOVENTRICULAR JUNCTIONAL TACHYCARDIAÌý The ventricular rate in paroxysmal atrial tachycardia (PAT) and in