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Figure 2 Electrocardiographic lead I4 of the body-surface map, at the baseline condition (A), with oral propranolol (B), during epinephrine infusion at baseline (C) and during epinephrine infusion with oral propranolol (D) in a patient with LQT2 syndrome. Both cQTe and cQTp were prolonged (545 and 429 ms, respectively) and cTp-e was increased (116 ms) at the baseline condition. Propranolol produced no significant change in cQTe (555 ms), but prolonged cQTp (454 ms), resulting in a decrease in cTp-e (101 ms). Epinephrine produced a prolongation in cQTe (630 ms), but a mild prolongation in cQTp (488 ms), resulting in an increase in cTp-e (142 ms), and this was completely suppressed by oral propranolol. HR = heart rate.