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11-08-2016 | Cardiology | News | Article

Brugada syndrome becoming less severe

medwireNews: The clinical presentation of the inherited cardiac arrhythmic disorder Brugada syndrome has become milder in the past 30 years, study findings indicate.

When compared with patients who presented before 2002,those identified between 2003 and2014 were significantly less likely to present with sudden cardiac death (SCD; 4.6 vs 12.1%) and significantly less likely to have a spontaneous type I electrocardiogram pattern at baseline (26.2 vs 50.3%).

Patients in the later cohort also had significantly fewer inducible ventricular arrhythmias during programmed electrical stimulation (19.2 vs 34.4%) and a significantly lower probability of recurrent arrhythmia during clinical follow-up (5.0 vs 19.0%).

“These variations in clinical presentation have important consequences”, say Ruben Casado-Arroyo (Université Libre de Bruxelles, Belgium) and co-authors of the study.

They write: “Newly diagnosed probands and family members have a more benign profile than patients diagnosed more than 25 years ago, probably due to the fact that we are starting a new era of the disease, with patients who are greater in number but who are less symptomatic.

“Also, an earlier diagnosis (clinical suspicion) and risk stratification can help the clinician prevent events during follow-up.”

The researchers found that the diagnosis of Brugada syndrome has increased significantly since its first description in 1992, as demonstrated by the fact that there were 165 probands in the early group and 282 in the later group.

In addition to the changes in clinical presentation, patients in the later group were also significantly less likely to present with an event (ventricular fibrillation, SCD or appropriate shock) during the mean 50-month follow-up period, with annual event rates of 1.8 versus 2.5.

Casado-Arroyo et al report in the Journal of the American College of Cardiology that a previous episode of SCD and inducibility of a sustained ventricular arrhythmia during electrophysiological study (EPS) were both significant predictors of events across the entire cohort, at hazard ratios of 11.6 and 4.2, respectively.

However, when the two groups were analysed separately, previous SCD and inducibility remained predictors of events in the early group, but only previous SCD predicted events in the later group.

This shows that “the value of inducibility to stratify individuals with [Brugada syndrome] has changed”, the researchers remark.

They conclude that although “more recently diagnosed patients seem to have a more favorable profile [...] follow-up of all patients until death is necessary to draw correct conclusions.”

Indeed, incomplete follow-up “may explain why in other series, some tests (like EPS) may not have had predictive value because the pre-test probability of a severe outcome (like SCD) may not have been sufficiently high as to allow recognition of significant differences.”

By Laura Cowen

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016