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We report the case of a 51-year-old patient with Brugada syndrome (BrS) who experienced inappropriate shock due to T-wave oversensing (TWOS) during exercise when the optimal sensing vector was selected based on the automatic analysis by a subcutaneous implantable cardioverter-defibrillator (S-ICD). After selecting another vector during exercise testing, TWOS did not re-occur. Selection of appropriate sensing vector based on analyses under various conditions, including during exercise after S-ICD implantation, should be considered for patients with BrS.

Loss-of-function mutations in the cardiac sodium channel α-subunit gene SCN5A result in multiple inherited arrhythmic syndromes. This case report describes 2 unrelated probands carrying an identical SCN5A frameshift mutation, V1764fsX1786, who exhibited distinct clinical manifestations: progressive cardiac conduction defect (PCCD)/Brugada syndrome (patient #1) and idiopathic ventricular fibrillation (IVF) (patient #2). Using a whole-cell patch clamp technique, cells expressing V1764fsX1786 showed no observable Na+ current. Therefore, a significant phenotypic overlap was found between IVF and PCCD/Brugada syndrome in the 2 probands with the V1764fsX1786, loss-of-function frameshift mutation of the cardiac sodium channel gene SCN5A.

Introduction: The aim of this study was to clarify the characteristics of lower loop reentry (LLR. in patients who underwent cardiac surgery. Methods: Of 194 patients from 2000 to 2007 with negative flutter waves in the inferior leads (II, III, and aVf), 4 patients had LLR and reentrant circuits identified by a 3D activation sequence mapping system. We studied the characteristics of the surface electrocardiogram (ECG. patterns of those LLRs. Results: All 4 patients had a history of an intracardiac operation. The 3D activation sequence mapping system during the LLR exhibited a clockwise (CW. wavefront around the inferior vena cava (IVC. from the caudal view. During the LLR, the right atrium (RA. free wall was activated in a caudal-cranial sequence and a collision of two activation wavefronts from the lower RA and upper RA occurred at the RA free wall. Conclusions: The 3D activation mapping during the AT revealed an activation wavefront propagating around the IVC and the diagnosis of LLR. Detailed 3D electroanatomical mapping and pacing study are needed to identify the reentrant circuit of LLR in patients with previous intracardiac surgery.