title: The effect of isolated left bundle branch block on the myocardial velocities and myocardial performance index.
abstract: OBJECTIVE
  This study was planned in order to investigate the effect of left bundle branch block (LBBB) on myocardial velocities obtained by tissue Doppler echocardiography (TDE) and myocardial performance index (MPI).
  
  
  METHODS
  Subjects with LBBB (n = 61) and age-matched healthy subjects (n = 60) were enrolled in the study. Left ventricular (LV) ejection fraction (EF), mitral inflow velocities (E-wave and A-wave), isovolumetric contraction and relaxation time (ICT and IRT), ejection time (ET), and flow propagation velocity (Vp) were measured by conventional echocardiography. Systolic velocity (Sm), early and late diastolic velocities (Em and Am) and time intervals were measured by TDE. MPI was calculated by the formula (ICT + IRT)/ET.
  
  
  RESULTS
  LVEF and mitral E/A ratio were similar in both groups. Vp was lower in the LBBB group than in the control group, whereas the E/Em and the E/Vp ratio was higher. LV Sm and Em/Am ratio were lower in LBBB group. Right ventricular Sm and Em/Am ratio were similar in both groups. LV mean and RV MPI were significantly increased in LBBB group.
  
  
  CONCLUSIONS
  These findings obtained by TDE show that isolated LBBB impairs the ventricular functions. Both of the LV and RV dysfunctions shown by the new parameters may contribute to increased morbidity and mortality in cases with isolated LBBB.
authors.affiliation: Department of Cardiology, Faculty of Medicine, Selcuk University, Konya, Turkey. akifduzenli@hotmail.com
authors.forename: Mehmet Akif
authors.initials: MA
authors.lastname: Duzenli
authors.forename: Kurtulus
authors.initials: K
authors.lastname: Ozdemir
authors.forename: Ahmet
authors.initials: A
authors.lastname: Soylu
authors.forename: Nazif
authors.initials: N
authors.lastname: Aygul
authors.forename: Mehmet
authors.initials: M
authors.lastname: Yazici
authors.forename: Mehmet
authors.initials: M
authors.lastname: Tokac
mesh_terms: D001783:Blood Flow Velocity; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D013318:Stroke Volume; D016277:Ventricular Function, Left