title: QRS Fragmentation and QTc Duration Relate to Malignant Ventricular Tachyarrhythmias and Sudden Cardiac Death in Patients with Hypertrophic Cardiomyopathy.
abstract: BACKGROUND
  QRS fragmentation (fQRS) and prolonged QTc interval on surface ECG are prognostic in various cardiomyopathies other than hypertrophic cardiomyopathy (HCM). The association between fQRS and prolonged QTc duration with occurrence of ventricular tachyarrhythmias or sudden cardiac death (VTA/SCD) in patients with HCM was explored.
  
  
  RESULTS
  One hundred and ninety-five clinical HCM patients were studied. QTc duration was derived applying Bazett's formula; fQRS was defined as presence of various RSR' patterns, R or S notching and/or >1 additional R wave in any non-aVR lead in patients without pacing or (in)complete bundle branch block. The endpoints comprised SCD, ECG documented sustained VTA (tachycardia or fibrillation) or appropriate implantable cardioverter defibrillator (ICD) therapies (antitachycardia pacing [ATP] or shock) for VTA in ICD recipients (n = 58 [30%]). QT prolonging drugs recipients were excluded. After a median follow-up of 5.7 years (IQR 2.7-9.1), 26 (13%) patients experienced VTA or SCD. Patients with fQRS in ≥3 territories (inferior, lateral, septal, and/or anterior) (p = 0.004) or QTc ≥460 ms (p = 0.009) had worse cumulative survival free of VTA/SCD than patients with fQRS in <3 territories or QTc <460 ms. fQRS in ≥3 territories (ß 4.5, p = 0.020, 95%CI 1.41-14.1) and QTc ≥460 ms (ß 2.7, p = 0.037, 95%CI 1.12-6.33) were independently associated with VTA/SCD. Likelihood ratio test indicated assessment of fQRS and QTc on top of conventional SCD risk factors provides incremental predictive value for VTA/SCD (p = 0.035).
  
  
  CONCLUSIONS
  Both fQRS in ≥3 territories and QTc duration are associated with VTA/SCD in HCM patients, independently of and incremental to conventional SCD risk factors.
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.|Sint-Jan Hospital Bruges, Department of Cardiology, Bruges, Belgium.
authors: Philippe
authors: P
authors: Debonnaire
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Spyridon
authors: S
authors: Katsanos
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Emer
authors: E
authors: Joyce
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Olivier V W
authors: OV
authors: VAN DEN Brink
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Douwe E
authors: DE
authors: Atsma
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Martin J
authors: MJ
authors: Schalij
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Jeroen J
authors: JJ
authors: Bax
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Victoria
authors: V
authors: Delgado
authors: Leiden University Medical Centre, Department of Cardiology, Leiden, the Netherlands.
authors: Nina Ajmone
authors: NA
authors: Marsan
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control; D017147:Defibrillators, Implantable; D018572:Disease-Free Survival; D004554:Electric Countershock / Q000295:instrumentation; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy
keywords: arrhythmia; electrocardiography; hypertrophy; risk factors; sudden death