Brugada-Like Changes in the Peripheral Leads during Diagnostic Ajmaline Test in Patients with Suspected Brugada Syndrome

Background: Although cases of Brugada-type electrocardiographic (ECG) pattern in peripheral (limb) leads have been reported ("atypical" Brugada syndrome [BS]), their incidence in patients investigated for BS is unknown. Methods: We retrospectively analyzed an ECG database collected during ajmaline test in 143 patients (89 men) with suspected BS. In 42 patients, 12-lead ECGs were recorded, whereas in 101 patients, leads V1-V3 from the third intercostal space were also recorded. The presence of types 1, 2, and 3 Brugada pattern in each limb and precordial lead was noted and the PR, QRS, and QTc intervals were calculated. Results: There were 114 (79.7%) negative and 29 (20.3%) positive tests. Type 1 pattern developed in >= 1 limb lead in six patients (4.2%) (3/29 with positive tests, 10.3%); all of them were male, symptomatic, and/or with family history of BS or sudden cardiac death. Their pre- and posttest QRS were significantly longer compared with the rest with positive (n = 26) or negative (n = 111) test (pretest: 129 +/- 31 ms vs 101 +/- 11 ms and 97 +/- 12 ms, P < 0.001; posttest: 175 +/- 44 ms vs 134 +/- 14 ms and 131 +/- 19 ms, P < 0.001). The posttest QTc was longer in patients with peripheral changes compared with the rest (507 +/- 47 ms vs 453 +/- 22 ms and 447 +/- 24 ms, P < 0.001). The pretest QTc and pre- and posttest heart rate and PR intervals were not significantly different between the three groups. Conclusions: Type 1 Brugada pattern in the peripheral leads was observed in 4.2% of patients during ajmaline test (10.3% of positive tests) and was associated with longer QRS and greater QTc prolongation compared with the rest of the patients. (PACE 2009; 32:695-703).