Left bundle branch block with and without coronary artery disease: which value for a tissue Doppler-derived post-systolic motion?
BACKGROUND
An asynchronous contraction occurring during a prolonged relaxation period, defined as post-systolic motion (PSM), has been described as being a consequence of coronary occlusion but also in other conditions including isolated left bundle branch block (LBBB). The aim of this study was to characterize PSM of the interventricular septum at pulsed tissue Doppler in LBBB with or without stenosis of the left anterior descending coronary artery (LAD).


METHODS
Forty-two patients with chronic, complete LBBB and tissue Doppler-derived septal PSM were divided into two groups on the basis of their coronary angiography: 27 without LAD stenosis and 15 with LAD stenosis (> or = 50%). Standard Doppler echocardiography and tissue Doppler of both the middle posterior septum and lateral mitral annulus were performed in the apical 4-chamber view.


RESULTS
Standard Doppler diastolic indexes were comparable between the two groups. Septal tissue Doppler showed lower myocardial systolic (Sm) and atrial peak velocities (both p < 0.05), a higher PSM (p < 0.005), and a longer relaxation time (p < 0.02) and pre-contraction time (p < 0.05) in patients with LAD stenosis. A Sm/PSM ratio < 1 was detected in 86% of patients with LAD stenosis and in 22% without LAD stenosis (sensitivity 73%, specificity 77%, positive predictive value 64%, negative predictive value 84%). Tissue Doppler of the mitral annulus showed a significantly longer relaxation time and pre-contraction time and a lower atrial velocity in the presence of LAD stenosis. In the overall population, PSM was positively associated with ejection fraction and negatively with age and septal thickness. In a multiple linear regression analysis, only LAD stenosis (beta = 0.42, p < 0.005) and ejection fraction (beta = 032, p = 0.03) were independent predictors of PSM (cumulative r2 = 0.27, p < 0.002).


CONCLUSIONS
Tissue Doppler may be useful to distinguish septal myocardial asynchrony in LBBB with and without LAD stenosis.
Citro
Rodolfo
R
Department of Cardiology, San Luca Hospital, Vallo della Lucania, SA, Italy.
Galderisi
Maurizio
M
Guarini
Pasquale
P
Cicala
Silvana
S
Mattioli
Domenico
D
Bianco
Antonio
A
de Divitiis
Oreste
O
Gregorio
Giovanni
G
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000379:methods; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D003935:Diagnostic Techniques, Cardiovascular; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016277:Ventricular Function, Left / Q000502:physiology