Where adenosine can effect ?according to SVTs classification!

Adenosine,in addition to terminating supraventricular tachycardia involving the atrioventricular (AV) node, may have antiarrhythmic effects on atrial tachycardia but it is not effective for Atrial flutter and fibrillation.
The electrophysiological effects of adenosine on supraventricular tissue include shortening of action potential duration in atrial myocytes mediated by the potassium current, IKAChAdO; shortening of action potential duration and hyperpolarization in sinus node cells;and anti- adrenergic electrophysiological effects resulting from inhibition of adenylylcyclase.
In addition to its well known effects on AV nodal reentry and AV reciprocating tachycardia,as well as its effects on ventricular tachycardia due to triggered activity,adenosine is useful as a diagnostic probe for suspected sinus node reentrantt achycardia.
Furthermore,because adenosine has no effect on reentrant atrial tachycardia but instead transiently suppresses automatic atrial tachycardia and terminates atrial tachycardia presumed due to triggered activity,adenosine may be useful in differentiating between these arrhythmias.
Responsiveness of triggered atrial tachycardia to adenosine may account for some instances where adenosine has been previously thought to terminate intra-atrial reentrant tachycardia.