title: Relationships between paced QRS duration and left cardiac structures and function.
abstract: BACKGROUND
  In patients with congestive heart failure, QRS duration (QRSd) is correlated with left ventricular (LV) ejection fraction (LVEF), ventricular dyssynchrony and patients' prognosis. However, little is known about the relationships between paced QRS duration (pQRSd) to cardiac structures and function and ventricular dyssynchrony in patients with chronic right ventricular apical (RVA) pacing, which were investigated in this study.
  
  
  METHODS
  Seventy patients implanted with DDD(R) pacemaker for high- or third-degree atrioventricular block were enrolled to study pQRSd and echocardiographic variables, including aortic root dimension (AO), left atrial dimension (LAD), LV end-systolic dimension (LVDs), LV end-diastolic dimension (LVDd), interventricular septum thickness (IVST), LV posterior wall thickness (LVPWT), LVEF, interventricular mechanical delay (IVMD), systolic asynchrony index (Ts-SD) and septal-to-lateral delay.The relationships between pQRSd and such variables were examined.
  
  
  RESULTS
  The pQRSd correlated positively with LVDd (r = 0.3166, P < 0.05), LVDs (r = 0.3741, P < 0.05), LAD (r = 0.5848, P < 0.01), IVST (r = 0.2925, P < 0.05), and negatively with LVEF (r = -0.3037, P < 0.05). No significant correlations were found between pQRSd and AO, LVPWT, IVMD, Ts-SD and septal-to-lateral delay (all P > 0.05). There was no significant correlation between LVEF and IVMD, Ts-SD, septal-to-lateral delay (P > 0.05). However, IVMD, Ts-SD and septal-to-lateral delay were greater in patients with low LVEF than in patients with normal LVEF (P < 0.05). A cut-off value for pQRSd of 180 ms had a sensitivity of 85.71% and a specificity of 66.67% to detect left atrial dilation.
  
  
  CONCLUSIONS
  pQRSd is correlated with left cardiac structures and LV systolic function. pQRSd > or =180 ms indicates left atrial dilation. There is no correlation between pQRSd and ventricular dyssynchrony.
authors.affiliation: Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, PR China.
authors.forename: Yangang
authors.initials: Y
authors.lastname: Su
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Pan
authors.forename: Xue
authors.initials: X
authors.lastname: Gong
authors.forename: Jie
authors.initials: J
authors.lastname: Cui
authors.forename: Xianhong
authors.initials: X
authors.lastname: Shu
authors.forename: Junbo
authors.initials: J
authors.lastname: Ge
mesh_terms: D000368:Aged; D016279:Atrial Function, Left / Q000502:physiology*; D054537:Atrioventricular Block / Q000503:physiopathology* / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D015150:Echocardiography, Doppler / Q000379:methods; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology*