Association between left ventricular mechanical dyssynchrony with myocardial perfusion and functional parameters in patients with left bundle branch block.
OBJECTIVE
To identify predictors of left ventricular mechanical dyssynchrony (LVMD) in patients with known left bundle branch block (LBBB) using gated single-photon emission computed tomography (SPECT) phase analysis.


METHODS
81 patients (74% male, 70 ± 10 years) with LBBB and suspected or known coronary artery disease underwent ECG-gated myocardial perfusion SPECT. LV perfusion and functional parameters were measured, and phase analysis was performed to quantify LV-dyssynchrony.


RESULTS
35/81 patients (42%) had prior myocardial infarction (MI), and the mean left ventricular ejection fraction (LVEF) was 49% ± 16%. LVMD was present in 58/81 (72%) patients. The summed thickening score (STS) (P < .001; odds ratio 1.22) emerged as independent predictor for the presence of LVMD in a multivariate regression model. In addition, prior MI, low LVEF, summed stress score, summed rest score, summed motion score, and LAD rest extent were identified as predictors of LVMD in a univariate model. Clinical baseline characteristics, cardiac risk factors, and QRS duration (P = .051) had no influence on the presence of LVMD.


CONCLUSIONS
In patients with LBBB, the occurrence of LVMD as assessed by gated SPECT phase analysis is mainly influenced by reduced myocardial contractility as expressed by the STS. Proper discrimination between LVMD arising from known electrical conduction delay as opposed to areas of MI causing reduced regional contractility seems to be mandatory for therapy planning in patients with LVMD.
Department of Nuclear Medicine, Ludwig-Maximilian's University, Munich, Germany.
Christopher
C
Uebleis
Xaver
X
Hoyer
Serge D
SD
Van Kriekinge
Franziska
F
Schuessler
Rüdiger Paul
RP
Laubender
Alexander
A
Becker
Sebastian
S
Lehner
Andrei
A
Todica
Alexander
A
Haug
Peter
P
Bartenstein
Paul
P
Cumming
Guido
G
Germano
Marcus
M
Hacker
D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging*; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging*