Background-Repolarization abnormalities in the inferior-lateral leads in Brugada syndrome (BS) have not been systematically investigated. Methods and Results-280 patients (age, 41Ϯ18 years; 168 males) with BS were screened for inferior-lateral repolarization abnormalities. The repolarization abnormalities were classified either as early repolarization pattern or coved Ն2-mm Brugada pattern and as spontaneous or class I antiarrhythmic drug (AAD) induced. Thirty-two patients (11%) had inferior-lateral spontaneous early repolarization pattern. These patients were less likely to be asymptomatic at first presentation (13 of 32 versus 156 of 248 patients, Pϭ0.02), and spontaneous type I ECG was more frequent among them (38% versus 21%, Pϭ0.05). The spontaneous early repolarization pattern occurred more frequently among patients with BS than in 283 family members not having BS (11% versus 6%, Pϭ0.03). Class I AAD administration provoked inferior-lateral coved Brugada pattern in 13 patients with BS. These patients had longer baseline PR intervals (206Ϯ48 versus 172Ϯ31 ms, PϽ0.001) and class I AAD-induced QRS interval prolongation (108 to 178 versus 102 ms to 131 ms, PϽ0.001). In 3 patients, the class I AAD-provoked coved Brugada pattern was only present in the inferior leads. Conclusions-Inferior-lateral early repolarization pattern occurs spontaneously relatively frequently in BS. These patients have a more severe phenotype. Class I AAD administration provokes inferior-lateral coved Brugada pattern in 4.6% of patients. We report for the first time 3 patients in whom the class I AAD-provoked coved Brugada pattern was only observed in the inferior leads. (Circ Arrhythmia Electrophysiol. 2009;2:154-161.)

Therapeutic, IV.