Figure 2.
(A) Extrastimulus pacing at baseline (left) and during isoproterenol infusion (right) in a patient with persistent AF. (B) Activation latency curves in the same patient, showing isoproterenol infusion (red) decreases maximum activation latency versus baseline (blue) and permits shorter extrastimuli to conduct. (C) APD restitution, for this patient, illustrate how isoproterenol (red) extends the curve to shorter diastolic intervals (leftward) versus baseline (blue), permitting shorter APDs and steepening APD restitution. (D) Premature extrastimulus induces AF in the same patient during isoproterenol, in whom no AF was observed at baseline.