title: Left bundle branch block in chronic heart failure-impact on diastolic function, filling pressures, and B-type natriuretic peptide levels.
abstract: BACKGROUND
  For patients with chronic heart failure (CHF), left bundle branch block (LBBB) is associated with impaired systolic function and increased morbidity and mortality, but data on diastolic function are scarce. In this patient population, we attempted to define the impact of LBBB on diastolic function, filling pressures, and brain natriuretic peptide and its circulating N-terminal precursor (NT-proBNP) levels.
  
  
  METHODS
  A total of 94 patients with stable CHF (48 with complete LBBB, 46 without intraventricular conduction delay and normal QRS duration) underwent conventional 2-dimensional/Doppler echocardiography and Doppler tissue analysis of mitral annular velocities. As a measure of left ventricular filling pressures, the ratio of peak early mitral flow velocity to peak early diastolic mitral annular velocity was derived. NT-proBNP measurements were carried out on a bench-top analyzer (Elecsys-2010, Roche Diagnostics, Mannheim, Germany).
  
  
  RESULTS
  Patients with or without LBBB did not differ with respect to the cause of CHF or ejection fraction, but in LBBB deceleration time was shorter (163 +/- 66 vs 205 +/- 95 milliseconds, P = .021) and a restrictive mitral filling pattern was more frequent (35% vs 11%, P = .005). In such patients, the ratio of peak early mitral flow velocity to peak early diastolic mitral annular velocity was higher (14.5 +/- 6.2 vs 10.6 +/- 5.2, P < .001) and NT-proBNP was elevated (3553 +/- 3725 vs 850 +/- 896 pg/mL, P < .01) as compared with patients without LBBB.
  
  
  CONCLUSIONS
  For patients with CHF and comparable systolic performance, LBBB is associated with more severe diastolic dysfunction, elevated filling pressures, and higher NT-proBNP levels. These findings may contribute to increased morbidity and mortality of such patients.
authors.affiliation: Department of Cardiology and Angiology, Hospital of the University of Münster, Münster, Germany. bruchc@uni-muenster.de
authors.forename: Christian
authors.initials: C
authors.lastname: Bruch
authors.forename: Joerg
authors.initials: J
authors.lastname: Stypmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Grude
authors.forename: Rainer
authors.initials: R
authors.lastname: Gradaus
authors.forename: Günter
authors.initials: G
authors.lastname: Breithardt
authors.forename: Thomas
authors.initials: T
authors.lastname: Wichter
mesh_terms: D001794:Blood Pressure; D002037:Bundle-Branch Block / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D013223:Statistics as Topic; D013318:Stroke Volume; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000097:blood* / Q000150:complications / Q000000981:diagnostic imaging*
chemical_list: D020097:Natriuretic Peptide, Brain