Using Electrocardiographic Activation Time and Diastolic Intervals to Separate Focal From Macro–Re-Entrant Atrial Tachycardias

Using Electrocardiographic Activation Time and Diastolic Intervals to Separate Focal From Macro–Re-Entrant Atrial Tachycardias Jason P. Brown, David E. Krummen, Gregory K. Feld, Sanjiv M. Narayan We tested whether accurate electrocardiographic (ECG) identification of shorter P or F waves relative to cycle length (CL) would identify focal from macro–re-entrant atrial tachycardia (AT). In 20 patients, P(F) waves overlying T waves were identified by slope transitions from T waves “expected” by scaling the sinus-rate T-wave. Compared with macro–re-entrant AT (n = 13), focal AT had shorter (p < 0.001) P waves that were smaller ratios of CL (p < 0.001). Applying receiver operating characteristic curve cutpoints prospectively (n = 21), P duration