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Aims Brugada syndrome (BrS) is associated with an increased risk of sudden cardiac death due to ventricular tachycardia/fibrillation (VT/VF) in young, otherwise healthy individuals. Despite SCN5A being the most commonly known mutated gene to date, the genotype–phenotype relationship is poorly understood and remains uncertain. This study aimed to elucidate the genotype–phenotype correlation in BrS. Methods and results Brugada syndrome probands deemed at high risk of future arrhythmic events underwent genetic testing and phenotype characterization by the means of epicardial arrhythmogenic substrate (AS) mapping, and were divided into two groups according to the presence or absence of SCN5A mutation. Two-hundred probands (160 males, 80%; mean age 42.6 ± 12.2 years) were included in this study. Patients harbouring SCN5A mutations exhibited a spontaneous type 1 pattern and experienced aborted cardiac arrest or spontaneous VT/VF more frequently than the other subjects. SCN5A-positive patients exhibited a larger epicardial AS area, more prolonged electrograms and more frequently observed non-invasive late potentials. The presence of an SCN5A mutation explained >26% of the variation in the epicardial AS area and was the strongest predictor of a large epicardial area. Conclusion In BrS, the genetic background is the main determinant for the extent of the electrophysiological abnormalities. SCN5A mutation carriers exhibit more pronounced epicardial electrical abnormalities and a more aggressive clinical presentation. These results contribute to the understanding of the genetic determinants of the BrS phenotypic expression and provide possible explanations for the varying degrees of disease expression.

Aims Continuous rhythm monitoring is valuable for adequate atrial fibrillation (AF) management in the clinical setting. Subcutaneous leadless implantable cardiac monitors (ICMs) yield an improved AF detection, overcoming the intrinsic limitations of the currently available external recording systems, thus resulting in a more accurate patient treatment. The study purpose was to assess the detection performance of a novel three-vector ICM device equipped with a dedicated AF algorithm. Methods and results Sixty-six patients (86.4% males; mean age 60.4 ± 9.4 years) at risk to present AF episodes, having undergone the novel ICM implant (BioMonitor, Biotronik SE&Co. KG, Berlin, Germany), were enrolled. External 48-h ECG Holter was performed 4 weeks after the device implantation. The automatic ICM AF classification was compared with the manual Holter arrhythmia recordings. Of the overall study population, 63/66 (95.5%) had analysable Holter data, 39/63 (62%) showed at least one true AF episode. All these patients had at least one AF episode stored in the ICM. On Holter monitoring, 24/63 (38%) patients did not show AF episodes, in 16 of them (16/24, 67%), the ICM confirmed the absence of AF. The AF detection sensitivity and positive predictive value for episodes' analysis were 95.4 and 76.3%, respectively. Conclusion Continuous monitoring using this novel device, equipped with a dedicated detection algorithm, yields an accurate and reliable detection of AF episodes. The ICM is a promising tool for tailoring individual AF patient management. Further long-term prospective studies are necessary to confirm these encouraging results.

The aim of this article is to understand the natural history of WPW syndrome to prevent sudden death is important to clinicians in establishing accurate prognosis and appropriate treatment. We report our experience on untreated WPW patients purely looking at the natural history of the disease. In a 15-year period (1995-2010), among 11 237 WPW patients referred to our Arrhythmology Department, a total of 1847 selected patients (820 symptomatic) underwent electrophysiological testing without ablation and were followed for a median (25th-75th) follow-up of 8 (5-8) years. During follow-up, malignant arrhythmias (MA) occurred in 16 patients (0.9%) of whom 14 (1.4%) were initially asymptomatic and two (0.2%) symptomatic (P = 0.01). Potentially MA developed in 143 patients (7.7%) without difference between asymptomatic and symptomatic population (P = 0.663). Benign recurrences developed in 295 patients (16%) while ventricular pre-excitation disappeared in 356 patients (19.3%) of whom 155 were initially asymptomatic. All patients were successfully ablated after arrhythmia occurrence. Patients with MA had similar accessory pathways antegrade refractory periods (AP-AERP) (P = 0.064) and more frequently inducible atrioventricular reciprocating tachycardia triggering atrial fibrillation (AVRT-AF) than those with potentially MA (P < 0.001). Symptoms did not predict MA, which were predicted by AP-AERP (HR 0.912, 95% CI 0.887-0.939, P < 0.001) and AVRT-AF (HR 8.306, 95% CI 2.269-30.405, P = 0.001). The natural history of WPW syndrome and the risk of sudden death essentially depend on intrinsic electrophysiological accessory pathway properties rather than on symptoms and electrophysiologic testing is the gold standard to identify patients at risk. The Authors encourage more intensive screening programs to identify asymptomatic patients at risk for prophylactic ablation.

We read with interest, pleasure, and satisfaction the recent study by Chun et al. 1 which definitively confirms our previous pivotal experience on the efficacy of remote ablation in hundreds of patients with single or multiple accessory pathways.2,3 However, in our experience, soft magnetic catheters (1 M, 3 M, or 3 M quadripolar) are all able to easily record the AP potential and once …