title: Relationship between QRS complex notch and ventricular dyssynchrony in patients with heart failure and prolonged QRS duration.
abstract: BACKGROUND
  Cardiac resynchronization therapy (CRT) has been accepted as an established therapy for advanced systolic heart failure. Electrical and mechanical dyssynchrony are usually evaluated to increase the percentage of CRT responders. We postulated that QRS notch can increase mechanical LV dyssynchrony independently of other known predictors such as left ventricular ejection fraction and QRS duration.
  
  
  METHODS
  A total of 87 consecutive patients with advanced systolic heart failure and QRS duration more than 120 ms with an LBBB-like pattern in V1 were prospectively evaluated. Twelve-lead electrocardiogram was used for detection of QRS notch. Complete echocardiographic examination including tissue Doppler imaging, pulse wave Doppler and M-mode echocardiography were done for all patients.
  
  
  RESULTS
  Eighty-seven patients, 65 male (75%) and 22 female (25%), with mean (SD) age of 56.7 (12.3) years were enrolled the study. Ischemic cardiomyopathy was the underlying heart disease in 58% of the subjects, and in the others it was idiopathic. Patients had a mean (SD) QRS duration of 155.13 (23.34) ms. QRS notch was seen in 49.4% of the patients in any of two precordial or limb leads. Interventricular mechanical delay was the only mechanical dyssynchrony index that was significantly longer in the group of patients with QRS notch. Multivariate analysis revealed that the observed association was actually caused by the effect of QRS duration, rather than the presence of notch per se.
  
  
  CONCLUSIONS
  QRS notch was not an independent predictor of higher mechanical dyssynchrony indices in patients with wide QRS complex and symptomatic systolic heart failure; however, there was a borderline association between QRS notch and interventricular delay.
authors.affiliation: Department of Pacemaker and Electrophysiology, Rajaie Cardiovascular Medical and Research Center, Teheran, Iran. fazelifar@gmail.com
authors.forename: Amir Farjam
authors.initials: AF
authors.lastname: Fazelifar
authors.forename: Hamid Reza
authors.initials: HR
authors.lastname: Bonakdar
authors.forename: Keivan
authors.initials: K
authors.lastname: Alizadeh
authors.forename: Hosein
authors.initials: H
authors.lastname: Azarnik
authors.forename: Majid
authors.initials: M
authors.lastname: Haghjoo
authors.forename: Hooman Bakhshandeh
authors.initials: HB
authors.lastname: Abkenar
authors.forename: Niloufar
authors.initials: N
authors.lastname: Samiei
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Sadr-Ameli
mesh_terms: D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D054143:Heart Failure, Systolic / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000150:complications / Q000175:diagnosis; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology