title: Fragmented narrow QRS complex: predictor of left ventricular dyssynchrony in non-ischemic dilated cardiomyopathy.
abstract: BACKGROUND
  Cardiac resynchronization therapy is an important therapeutic modality in drug refractory symptomatic patients of heart failure with wide QRS (≥120 ms) on electrocardiogram. However, wide QRS (considered as a marker of electrical dyssynchrony) occurs in only 30% of heart failure patients, making majority of drug refractory heart failure patients ineligible for resynchronization therapy. Significant numbers of patients with narrow QRS have echocardiographic evidence of left ventricular dyssynchrony. However, there is sparse data about additional features on the surface ECG which can predict intraventricular dyssynchrony. This study was undertaken to assess the utility of fragmented narrow QRS complex to predict significant intraventricular dyssynchrony in symptomatic patients of non-ischemic dilated cardiomyopathy.
  
  
  METHODS
  100 symptomatic patients of non-ischemic dilated cardiomyopathy with narrow QRS complexes (50 each with fragmented and normal QRS) were recruited. Tissue Doppler imaging was used to assess intraventricular dyssynchrony as per 'Yu index'.
  
  
  RESULTS
  78% patients (n = 39) in fQRS complex group and 14% (n = 7) in normal QRS complex group had significant intraventricular dyssynchrony (χ(2) = 20.61; p < 0.000005). fQRS complexes had 84.78% sensitivity, 79.62% specificity, a positive predictive value of 78% and negative predictive value of 86% to detect intraventricular dyssynchrony. fQRS also had sensitivity and specificity of 93% and 90% respectively to localize the dyssynchronous segment.
  
  
  CONCLUSIONS
  fQRS is a marker of electrical dyssynchrony, which results in significant intraventricular dyssynchrony in patients of non-ischemic dilated cardiomyopathy and a narrow QRS interval. fQRS localizes the dyssynchronous segment and might be useful in identifying patients who can benefit from cardiac resynchronization therapy.
authors: Department of Cardiology, G.B. Pant Hospital, New Delhi, India.
authors: Jamal
authors: J
authors: Yusuf
authors: Devendra Kumar
authors: DK
authors: Agrawal
authors: Saibal
authors: S
authors: Mukhopadhyay
authors: Vimal
authors: V
authors: Mehta
authors: Vijay
authors: V
authors: Trehan
authors: Sanjay
authors: S
authors: Tyagi
mesh_terms: D002311:Cardiomyopathy, Dilated / Q000503:physiopathology*; D018618:Echocardiography, Doppler, Color; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*
references: Clin Cardiol. 2004 Mar;27(3):151-3
references: 15049383
references: Heart. 2004 May;90(5):479-81
references: 15084530
references: Eur J Echocardiogr. 2005 Dec;6(6):455-60
references: 16293532
references: Circulation. 1994 Jun;89(6):2879-87
references: 8205704
references: N Engl J Med. 2007 Dec 13;357(24):2461-71
references: 17986493
references: J Am Coll Cardiol. 2002 Aug 7;40(3):536-45
references: 12142123
references: J Am Soc Echocardiogr. 2008 Mar;21(3):191-213
references: 18314047
references: N Engl J Med. 2004 May 20;350(21):2140-50
references: 15152059
references: N Engl J Med. 2005 Apr 14;352(15):1539-49
references: 15753115
references: Eur J Heart Fail. 2007 May;9(5):484-90
references: 17347038
references: J Am Coll Cardiol. 1995 May;25(6):1263-72
references: 7722119
references: Can J Cardiol. 2009 Sep;25(9):517-22
references: 19746241
references: J Am Coll Cardiol. 2008 May 27;51(21):e1-62
references: 18498951
references: J Am Coll Cardiol. 2006 Dec 5;48(11):2243-50
references: 17161254
references: Circulation. 2008 May 20;117(20):2608-16
references: 18458170
references: Am J Cardiol. 2003 Mar 15;91(6):684-8
references: 12633798
references: Circulation. 2006 May 30;113(21):2495-501
references: 16717150
references: J Am Soc Echocardiogr. 1989 Sep-Oct;2(5):358-67
references: 2698218
references: Am J Cardiol. 2003 Nov 15;92(10):1238-40
references: 14609610
references: J Am Coll Cardiol. 2006 Dec 5;48(11):2251-7
references: 17161255
references: Echocardiography. 2011 Jan;28(1):62-8
references: 20618390
references: J Am Coll Cardiol. 2004 Nov 2;44(9):1834-40
references: 15519016
references: J Am Coll Cardiol. 2005 Dec 20;46(12):2183-92
references: 16360044
references: Int J Cardiol. 2008 Mar 14;124(3):293-300
references: 17442428
references: J Am Coll Cardiol. 2003 Dec 17;42(12):2117-24
references: 14680737
references: Heart. 2003 Jan;89(1):54-60
references: 12482792
references: Pacing Clin Electrophysiol. 2007 May;30(5):616-22
references: 17461871
references: Am J Cardiol. 2005 Jan 1;95(1):140-2
references: 15619414
references: Circulation. 1997 May 20;95(10):2423-33
references: 9170406
references: J Am Coll Cardiol. 2007 Feb 20;49(7):778-83
references: 17306707
references: J Am Coll Cardiol. 2004 Dec 7;44(11):2157-65
references: 15582313
references: J Cardiovasc Electrophysiol. 2004 Sep;15(9):1058-65
references: 15363081