Profound hypotension due to slow atrioventricular nodal pathway conduction during atrial tachycardia.

Paroxysmal supraventricular tachycardia (SVT) may have a variety of hemodynamic effects depending on rate, patient volume status, and presence of structural heart disease or left bundle branch block. We report a case of a patient with atrial tachycardia and dual atrioventricular (AV) nodal physiology who developed profound hypotension during transition from fast to slow AV nodal pathway conduction, despite similar tachycardia cycle length. This case illustrates the potential importance of AV timing in determining the hemodynamic effect of SVT.