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Figure 4 Relationship Between Appearance of Type 1 ECG and Each Parameter

Relationship between appearance of type 1 electrocardiogram (ECG) and differences in activation-recovery interval corrected for heart rate (ARIc) (A), repolarization time corrected for heart rate (RTc) (B), and activation time (AT) (C) in control subjects (Control) and in patients with Brugada syndrome (Brugada) under baseline conditions (Baseline) and after the administration of pilsicainide (After Pilsicainide). (A) Type 1 ECG was closely related to the prolongation of ARIc in the epicardium compared with that in the endocardium. The difference in ARIc with type 1 ECG was significantly larger than that without type 1 ECG under baseline conditions (p < 0.0001). After the administration of pilsicainide, type 1 ECG appeared and the difference in ARIc was more than 0 ms in all patients with Brugada syndrome. (B) Epicardial RTc was always longer than endocardial RTc in patients manifesting type 1 ECG regardless of pilsicainide administration. The difference in RTc with type 1 ECG was significantly larger than that without type 1 ECG in Brugada syndrome patients under baseline conditions (p < 0.00001). (C) The difference in AT with type 1 ECG was significantly larger than that without type 1 ECG in Brugada syndrome patients under baseline conditions (p < 0.05). However, the difference in AT was a less critical factor determining type 1 ECG than was the difference in RTc or ARIc. Open black circles = type 1 ECG was recorded in surface ECG without SCN5A mutation; open blue circles = type 1 ECG was recorded in surface ECG with SCN5A mutation; open diamonds = type 1 ECG was not recorded in surface ECG.