Abstract 1832: Location of Making Type 1 Electrocardiogram in Brugada Syndrome: Comparison between Lead Position and Anatomical Location of Right Ventricular Outflow Tract
Introduction: Recording type 1 ECG in right precordial leads in the presence or absence of a sodium channel blocker is a diagnostic criterion in Brugada syndrome (BrS). It was also suggested that right ventricular outflow tract (RVOT) is the arrhythmogenic substrate in BrS. However, we occasionally observed type 1 ECG only in the third intercostal space (3ics), not standard fourth intercostal space (4ics). Accordingly, we examined the relationship between the position of ECG leads manifesting type 1 and anatomical location of RVOT under fluoroscopic image.
Methods: Total 33 BrS patients were examined in this study. All patients had more than one of the following: documented ventricular fibrillation (VF), several episodes of syncope, a family history of sudden death, SCN5A mutation or inducibility of VF by programmed electrical stimulation. Anatomical location of the RVOT was determined under fluoroscopic image with right ventriculography. ECG was also recorded at the 3ics in leads V1 and V2 in addition to the standard V1 and V2 at the 4ics with fluoroscopically visible electrodes. A pure sodium channel blocker, pilsicainide, was administered in all patients without manifesting type 1 ECG under baseline conditions. Relationships between anatomical location and the position of ECG leads manifesting type 1 were examined in all patients.
Results: Type 1 ECG was recorded in all patients with pilsicainide administration. The location of RVOT corresponded with lead V1 and V2 at the 4ics in 5 patients and at the 3ics in 28 patients. In 4 out of 5 patients (80.0%) corresponding RVOT with 4ics, type 1 ECG was recorded at the 4ics. However, in 24 out of 28 patients (85.7%) corresponding RVOT with 3ics, type 1 ECG was recorded only at the 3ics. Furthermore, in 7 out of 12 symptomatic patients (58.3%) with documented VF or syncope, type 1 ECG was not recorded at the 4ics, however, could be detected at the 3ics without pilsicainide administration. The location of RVOT was not different between symptomatic and asymptomatic patients.
Conclusions: Type 1 ECG is predominantly caused at the RVOT, and the relationship between the position of ECG lead and the RVOT is variable. Recording ECG at the 3ics in addition to the standard 4ics in the right precordial leads is convincing in diagnosis of BrS.