title: Risk factors for QRS prolongation after repaired tetralogy of Fallot.
abstract: BACKGROUND
  Repaired tetralogy of Fallot is usually conducive to a normal and unrestricted lifestyle. However, occasionally, late sudden death occurs due to ventricular tachycardia. This is thought to be due to a combination of factors, including both left and right ventricular dilation, which may be associated with valvular incompetence and residual right ventricular outflow tract obstruction. Several studies have shown that QRS duration > 180 ms is a predictor for life-threatening ventricular arrhythmias.
  
  
  RESULTS
  We recalled our tetralogy population (n = 57) to identify risk factors for prolonged QRS duration on the resting ECG. Factors examined included history, demographics, symptoms, surgery, chest X-ray, ECG and echocardiography. Extensive analysis found only a significant positive correlation between QRS duration and degree of residual right ventricular outflow tract obstruction.
  
  
  CONCLUSIONS
  Our study suggests that residual right ventricular outflow tract gradients may be a very significant contributor to QRS prolongation. It will be interesting to see if future studies of larger cohorts confirm this finding.
authors.affiliation: Paediatric Department, St. Luke's Hospital, Guardamangia, Malta. nathaliegalea1@hotmail.com
authors.forename: Nathalie
authors.initials: N
authors.lastname: Galea
authors.forename: Oscar
authors.initials: O
authors.lastname: Aquilina
authors.forename: Victor
authors.initials: V
authors.lastname: Grech
mesh_terms: D000293:Adolescent; D000328:Adult; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002648:Child; D018619:Echocardiography, Doppler, Pulsed; D004562:Electrocardiography; D006801:Humans; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D011183:Postoperative Complications; D011379:Prognosis; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D013771:Tetralogy of Fallot / Q000150:complications / Q000503:physiopathology / Q000601:surgery*