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P6587The experience of a French specialized inherited arrhythmia center in the management of long QT syndrome patients


 
 
 Congenital long QT syndrome (LQTS) is a hereditary disease characterized by prolonged QTc interval and risk of ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest, or sudden death in young people.
 
 
 
 The aim of this study is to report the experience of the French referral center of inherited arrhythmia of the University Hospital of Nantes.
 
 
 
 Consecutive patients affected with lonq QT syndrome were recruited in a multicentric prospective registry in France (15 centers) between 1997 and 2018. Clinical data and 12-lead ECG were collected. Genetic screening was performed using dHPLC-DNA sequencing, HRM or targeted sequencing for at least KCNQ1, KCNH2 and SCN5A.
 
 
 
 In this study, we enrolled a total of 741 patients affected by LQTS according to the Schwartz score (447 (60%) females, 404 (55%) index cases). Mean age at diagnosis was 33±21 years. In this cohort, 343 patients (46%) were symptomatic: 66 patients experienced resuscitated sudden cardiac death (SCD, 9%), 211 (28%) syncope and 66 (9%) ventricular arrhythmias. One hundred and two patients (14%) had history of familial SCD. At baseline, heart rate was 69±19 bpm, PR 149±39 mm, QRS 86±16 mm and QTc 479±62 mm.
 Three hundred and eighty-six patients (52%) were treated with beta-blockers and 88 patients (12%) were implanted with an ICD.
 Genetic screening was performed in 668 (90%) patients. Genetic screening for the 3 major genes of LQTS was positive for 411 patients (62%): 165 variants (25%) in KCNQ1, 178 variants (27%) in KCNH2, 68 variants (10%) in SCN5A. Moreover, we found variants in minor genes of LQTS for 22 patients (3%).
 During a mean follow-up of 6.2±5.2 years, 64 patients (9%) underwent arrhythmic events (7 SCD (1%), 8 appropriate ICD therapy (1%) and 49 ventricular arrhythmias (7%). The rate of arrhythmic event was 1.39%/y. Mean age at the first event was 41.7±21.5 years. Sixteen patients (2%) died of non-arrhythmic causes.
 
 
 
 Care in a specialized inherited arrhythmia center is associated with a low incidence of arrhythmic event (1.39%/y) in patients affected with LQTS.
