Utility of atrial and ventricular cycle length variability in determining the mechanism of paroxysmal supraventricular tachycardia.

were 83%, 100%, 100%, and 95%, respectively. The corresponding values for the change in atrial CL being predicted by the change in the preceding ventricular CL for typical AVNRT or ORT were 85%, 97%, 99%, and 65%, respectively. Conclusion: Tachycardia CL variability ≥15 msec is common in PSVT. A change in atrial CL that predicts the change in subsequent ventricular CL strongly favors AT or atypical AVNRT. A change in atrial CL that is predicted by the change in the preceding ventricular CL favors typical AVNRT or ORT. (J Cardiovasc