title: New echocardiographic insights in short QT syndrome: More than a channelopathy?
abstract: BACKGROUND
  Short QT syndrome (SQTS) is a congenital ion channel disease characterized by an increased risk of sudden cardiac death. Little is known about the possibility that accelerated repolarization alters mechanical function in SQTS.
  
  
  OBJECTIVE
  The study investigated the presence of left ventricular dysfunction and mechanical dispersion, assessed by tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE), and their correlation with QT interval duration and genetics.
  
  
  METHODS
  Fifteen SQTS patients (7 with HERG and 3 with KCNQ1 mutation) were studied. Electrocardiographic and echocardiographic parameters were compared with age- and sex-matched healthy controls.
  
  
  RESULTS
  When compared to the control group, SQTS patients showed reduced left ventricular contraction (global longitudinal strain: -16.0% ± 3.4% vs -22.6% ± 1.7%, P < .001; myocardial performance index 0.59 ± 0.17 vs 0.34 ± 0.08, P < .001) and a higher incidence of ejection fraction <55% (odds ratio 11, 95% confidence interval 1.045-374, P = .04). Mechanical dispersion assessed by TDI (P < .01) and STE (P < .001) was higher in the SQTS group than in controls; each parameter showed a significant inverse correlation with QT interval but not with QT dispersion.
  
  
  CONCLUSIONS
  This study showed that in SQTS systolic function may also be affected. SQTS patients presented a significant dispersion of myocardial contraction. TDI and STE could become part of the evaluation of this rare disease.
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Frea
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Giustetto
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Capriolo
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Scrocco
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Fornengo
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Benedetto
authors.affiliation: Division of Cardiology, Mauriziano Hospital, Turin, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bianchi
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy,. Electronic address: stefano.pidello@gmail.com.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pidello
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Morello
authors.affiliation: Division of Cardiology, University of Turin, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Turin, Italy.
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Gaita
mesh_terms: D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging* / Q000235:genetics / Q000503:physiopathology; D053447:Channelopathies / Q000151:congenital / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D015150:Echocardiography, Doppler / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*; D055815:Young Adult
keywords: Arrhythmias; Genetics; Global longitudinal strain; Short QT syndrome; Speckle tracking echocardiography; Tissue Doppler imaging