Longer Repolarization in the Epicardium at the Right Ventricular Outflow Tract Causes Type 1 Electrocardiogram in Patients With Brugada Syndrome
Satoshi Nagase, MD*,
Kengo Fukushima Kusano, MD,
Hiroshi Morita, MD,
Nobuhiro Nishii, MD,
Kimikazu Banba, MD,
Atsuyuki Watanabe, MD,
Shigeki Hiramatsu, MD,
Kazufumi Nakamura, MD,
Satoru Sakuragi, MD and
Tohru Ohe, MD
Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
View larger version (80K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 1 Catheter Position
Fluoroscopic right anterior oblique (RAO) (A) and left anterior oblique (LAO) (B) views of the position of the electrical guidewire for epicardial mapping (RVOT-epi), as well as the quadripolar catheter at the endocardium of the free wall at the RVOT for endocardial mapping (RVOT-endo).
|
|
View larger version (13K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 2 Example of Surface Electrocardiograms (II, V2, and V5) and Intracardiac Unipolar Electrogram at the RVOT
Activation-recovery interval (ARI), repolarization time (RT), and activation time (AT) were measured at the right ventricular outflow tract (RVOT).
|
|
View larger version (39K):
[in this window]
[in a new window]
[Download PPT slide]
|
Figure 3 Patient Examples
Representative surface ECGs and unipolar electrograms in a control subject (A) and in 2 patients with Brugada syndrome (B and C) under baseline conditions (left panels) and after pilsicainide administration (right panels). (A) Brugada-type ECG was not observed in surface ECGs. Under baseline conditions, the epicardial ARI (221 ms) was shorter than the endocardial ARI (244 ms). After the administration of pilsicainide, the epicardial ARI (208 ms) was still shorter than the endocardial ARI (230 ms). (B) Under baseline conditions, type 1 ECG was observed in lead V2(3ics) (*), and the epicardial ARI (239 ms) was longer than the endocardial ARI (187 ms). After the administration of pilsicainide, type 1 ECG was still observed in lead V2(3ics) (*), and epicardial ARI (222 ms) was longer than endocardial ARI (190 ms). (C) Under baseline conditions, type 1 ECG was not observed in any of the surface ECG leads, and the epicardial ARI (210 ms) was shorter than endocardial ARI (248 ms). However, after administration of pilsicainide, the epicardial ARI, but not the endocardial ARI, was markedly prolonged (260 ms), and type 1 ECG appeared in lead V2(3ics) (*). The epicardial ARI was 18 ms longer than the endocardial ARI (242 ms). Numbers indicate ARI. ARI = activation-recovery interval; ECG = electrocardiogram; RVOT-epi = uniploar electrogram of the epicardium at the right ventricular outflow tract; RVOT-endo = uniploar electrogram of the endocardium at the right ventricular outflow tract; * = type 1 ECG.
|
|
View larger version (11K):
[in this window]
[in a new window]
[Download PPT slide]
|
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.
|
|
|
