Left ventricular twist was decreased in isolated left bundle branch block with preserved ejection fraction.
OBJECTIVE
Left ventricular (LV) rotation and twist play an important role in LV contraction and relaxation. Left bundle branch block (LBBB) deteriorates both diastolic and systolic functions. We evaluated the LV twist in patients with LBBB and preserved ejection fraction (EF) (>50%) to determine twist as a potential marker for subtle myocardial dysfunction.


METHODS
This observational cross-sectional study included 34 LBBB patients with preserved EF who were free from ischemic and valvular disease (Group 1) and 36 healthy controls (Group 2). All patients underwent 2-D Doppler and 2-D speckle tracking echocardiography. LV apical, basal rotation, and twist were evaluated in both groups and compared accordingly. In addition, subjects were dichotomized considering the median twist value of the study population. Binary logistic regression analysis was performed to determine the independent variables associated with inframedian twist.


RESULTS
Baseline clinical characteristics were similar in LBBB patients and controls. Mean apical rotation (2.5°±1.9° vs. 4.4°±2.9°; p=0.002), basal rotation (-2.9°±2.3° vs. -4.1°±2.7°; p=0.05), and twist (5.4°±3° vs. 8.6°±3.3°; p<0.001) were decreased in group 1. Parameters related to intra- and interventricular mechanical dyssynchrony, such as longitudinal left ventricular dyssynchrony index (LVdys) and preejection interval of LV, interventricular mechanical delay (IVMD), and left posterior wall contractions (SPMWD) were significantly higher in the LBBB group. The median twist value of the studied population was 6.65°. Binary logistic regression analysis showed that only presence of LBBB was independently associated with inframedian twist (OR=6.250; 95% CI: 2.215-17.632; p<0.001).


CONCLUSIONS
The LBBB might have induced the reduction of LV twist by diminishing the LV rotation before inducing a prominent effect on the left ventricular ejection fraction (LVEF). Therefore, twist may be considered as a marker for subtle LV dysfunction in LBBB with substantially normal EF.
Department of Cardiology, Faculty of Medicine, Sakarya University; Sakarya-Turkey. ssevincdr@gmail.com.
Sabiye
S
Yılmaz
Harun
H
Kılıc
Mustafa Tarık
MT
Ağac
Nurgül
N
Keser
Efe
E
Edem
Saadet
S
Demirtaş
Mehmet Bülent
MB
Vatan
Ramazan
R
Akdemir
Hüseyin
H
Gündüz
D000368:Aged; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004452:Echocardiography; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012399:Rotation; D013318:Stroke Volume; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*