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Aims Brugada syndrome (BrS) is a rare heritable ventricular arrhythmia. Genetic defects in SCN5A , a gene that encodes the α-subunit of the sodium ion channel Nav1.5, are present in 15–30% of BrS cases. SCN5A remains by far, the highest yielding gene for BrS. We studied a young male who presented with syncope at age 11. This proband was screened for possible disease causing SCN5A mutations. The inheritance pattern was also examined amongst his first-degree family members. Methods and results The proband had a baseline electrocardiogram that showed Type 2 BrS changes, which escalated to a characteristic Type I BrS pattern during a treadmill test before polymorphic ventricular tachycardia onset at a cycle length of 250 ms. Mutational analysis across all 29 exons in SCN5A of the proband and first-degree relatives of the family revealed that the proband inherited a compound heterozygote mutation in SCN5A , specifically p.A226V and p.R1629X from each parent. To further elucidate the functional changes arising through these mutations, patch-clamp electrophysiology was performed in TSA201 cells expressing the mutated SCN5A channels. The p.A226V mutation significantly reduced peak sodium current ( I Na) to 24% of wild type (WT) whereas the p.R1629X mutation abolished the current. To mimic the functional state in our proband, functional expression of the compound variants A226V + R1629X resulted in overall peak I Na of only 13% of WT ( P < 0.01). Conclusion Our study is the first to report a SCN5A compound heterozygote in a Singaporean Chinese family. Only the proband carrying both mutations displayed the BrS phenotype, thus providing insights into the expression and penetrance of BrS in an Asian setting.

Aims Implantable cardioverter defibrillators (ICDs) reduce sudden death in patients at high risk. High defibrillation thresholds (DFTs) are not uncommon and may be the cause of failed defibrillation in patients with ICDs. Addition of a coil in the azygous vein posterior to the heart lowers the DFT in most patients by altering the electrical vector during defibrillation. This can be accomplished fairly easily and expeditiously using standard equipment in the laboratory. It also avoids the difficulties and complications associated with other methods such as the use of a subcutaneous array. Methods and results This series of three cases illustrates the type of patients who may benefit from this technique. The addition of an azygous coil successfully lowered the DFT to

Early recurrences of atrial arrhythmia after wide electrically isolating ablation for atrial fibrillation (AF) are well described, but the long-term risk of recurrence for patients with persistent and permanent AF has not been studied in detail. METHODS AND RESULTS Fifty-six consecutive patients [45 men (80.4%), age 55.9 +/- 8.7 years] with persistent [39(69.6%)] or permanent [17(30.4%)] AF were followed for 21.6 +/- 8.8 months after ablation. Atrial fibrillation duration prior to ablation was 6.4 +/- 5.6 years. Electrically isolating lesions encircling the left and right pulmonary veins (PVs) in pairs were created. After 1.5 +/- 0.7 procedures, 48 (85.7%) had sinus rhythm (SR) at 21.6 +/- 8.8 months of follow-up: achieved with 1 procedure in 27 (56.3%) and without anti-arrhythmics in 30 (62.5%). Atrial fibrillation recurrence was observed in 69.6% after the first and 46.4% after the last procedure. Of those with late recurrences (90 days) following the last procedure, most [18 (69.2%)] did not have early recurrences. Pre-procedural AF duration (P = 0.007) and female gender (P = 0.005) were independent predictors of recurrence following the last procedure.Circumferential PV isolation is effective in most patients with persistent or permanent AF. However, repeat procedures are frequently required. Late recurrences are common and not precluded by the absence of early post-procedural arrhythmias.

A patient with ischaemic cardiomyopathy was found dead 3 months after the implantation of a primary prevention biventricular cardioverter-defibrillator. The last event on his device showed correct detection of ventricular tachycardia (VT) in the VT-2 zone. However, defibrillation was inhibited during redetection …