Systolic and diastolic regional myocardial motion of pacing-induced versus idiopathic left bundle branch block with and without left ventricular dysfunction.
To demonstrate systolic and diastolic asynchrony in patients with left bundle branch block (LBBB), tissue Doppler imaging (TDI) of 4 different walls was performed in 27 normal controls, 29 patients with right ventricular pacing and normal left ventricular (LV) ejection fraction (EF; pacing LBBB), and 35 patients with idiopathic LBBB. Patients with idiopathic LBBB were further classified into those with LVEF >50% and those with LVEF <35%. Asynchrony was calculated as the coefficient of variation of the time intervals from the QRS complex to the peak systolic velocity and to the peak of early diastolic relaxation. Patients with pacing and idiopathic LBBB had significantly longer QRS durations (162 +/- 20 vs 92 +/- 7 ms, p <0.001) and larger systolic (15.9 +/- 5.0% vs 4.1 +/- 2.1%, p <0.001) and diastolic (3.7 +/- 2.0% vs 1.4 +/- 0.6%, p <0.001) asynchrony than controls. Those with idiopathic LBBB and low EF had significantly larger diastolic asynchrony (5.7 +/- 2.1%) than those with pacing LBBB (2.9 +/- 1.1%) and those with idiopathic LBBB and normal EF (2.0 +/- 0.6%). Diastolic asynchrony was the only independent factor that correlated with LVEF (r = -0.64, p <0.001). Thus, idiopathic LBBB with LV dysfunction is characterized not only by systolic but also by diastolic asynchrony.
Kang
Soo-Jin
SJ
Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-dong Songpa-ku, Seoul 138-040, South Korea.
Song
Jae-Kwan
JK
Yang
Hyun Suk
HS
Song
Jong-Min
JM
Kang
Duk-Hyun
DH
Rhee
Kyoung-Suk
KS
Nam
Gi-Byoung
GB
Choi
Kee-Joon
KJ
Kim
Jae-Joong
JJ
Kim
You-Ho
YH
D000328:Adult; D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D016022:Case-Control Studies; D003971:Diastole; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*