Long-Term Follow-Up of Patients With Short QT Syndrome

Long-Term Follow-Up of Patients With Short QT Syndrome GIUSTETTO, Carla ; Rainer Schimpf; Andrea Mazzanti; Chiara Scrocco; Philippe Maury; Olli Anttonen; Vincent Probst; Jean Jacques Blanc; Pascal Sbragia; DALMASSO, Paola ; Martin Borggrefe; Fiorenzo Gaita 2011-01-01 Abstract Objectives. The aim of this study was to investigate the clinical characteristics and the long-term course of a large cohort of patients with Short QT Syndrome (SQTS). Background. SQTS is a rare channelopathy characterized by an increased risk of sudden death (SD). Data on the long-term outcome of SQTS patients are not available. Methods. Fifty-three patients from the European short QT Registry (75% males; median age 26 years) were followed for 64±27 months. Results. A familial or personal history of cardiac arrest was present in 89%. SD was the clinical presentation in 32%. The average QTc 314±23 ms. A mutation in genes related to SQTS was found in 23% of the probands; most of them had a gain of function mutation in HERG (SQTS1). Twenty-four patients received an implantable cardioverter defibrillator (ICD) and 12 long-term prophylaxis with hydroquinidine (HQ), which was effective in preventing the induction of ventricular arrhythmias. Patients with a HERG mutation had shorter QTc at baseline and a greater QTc prolongation following treatment with HQ. During follow-up, 2 already symptomatic patients received appropriate ICD shocks and one had syncope. Non-sustained polymorphic ventricular tachycardia was recorded in 3 patients. The event rate was 4.9% per year in the patients without antiarrhythmic therapy. No arrhythmic events occurred in patients receiving HQ. Conclusions. SQTS carries a high risk of SD, in all age groups. Symptomatic patients have a high risk of recurrent arrhythmic events. HQ is effective in preventing ventricular tachyarrhythmias induction and arrhythmic events during long-term follow-up.