Key result
Isolated left bundle branch block impaired ventricular functions, significantly increasing left and right ventricular myocardial performance index compared to healthy controls.
Why the study?
Does isolated left bundle branch block impair ventricular function as measured by tissue Doppler echocardiography and myocardial performance index?
Case-Control (n=121)
Does isolated left bundle branch block impair ventricular function as measured by tissue Doppler echocardiography and myocardial performance index?
Isolated LBBB is associated with impaired left and right ventricular function as measured by tissue Doppler echocardiography and myocardial performance index.
May signal subclinical biventricular dysfunction despite preserved EF; leaves open MPI's prognostic value in prospective LBBB cohorts.
OBJECTIVES: 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. CONCLUSION: 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.
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Düzenli et al. (2007) conducted a case-control in Isolated left bundle branch block (n=121). Isolated left bundle branch block vs. Healthy subjects was evaluated on Myocardial velocities and myocardial performance index. Isolated left bundle branch block impaired ventricular functions, significantly increasing left and right ventricular myocardial performance index compared to healthy controls.
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