Left bundle branch block with and without coronary artery disease: which value for a tissue Doppler-derived
Rodolfo Citro1, Maurizio Galderisi, Pasquale Guarini
1Department of Cardiology, San Luca Hospital, Vallo della Lucania, SA, Italy.
Insights
Post-systolic motion (PSM) in left bundle branch block (LBBB) patients with left anterior descending (LAD) stenosis shows distinct tissue Doppler patterns. Tissue Doppler imaging can differentiate septal myocardial asynchrony in LBBB with or without LAD stenosis.
Area of Science:
- Cardiology
- Echocardiography
- Myocardial Mechanics
Background:
- Post-systolic motion (PSM) is an asynchronous contraction during relaxation, linked to coronary occlusion and left bundle branch block (LBBB).
- Characterizing PSM in LBBB, with or without left anterior descending (LAD) artery stenosis, is crucial for understanding myocardial mechanics.
Purpose of the Study:
- To characterize septal post-systolic motion (PSM) using pulsed tissue Doppler in patients with left bundle branch block (LBBB).
- To differentiate PSM patterns in LBBB patients with and without left anterior descending (LAD) artery stenosis.
Main Methods:
- Forty-two patients with chronic, complete LBBB and septal PSM were analyzed.
- Patients were grouped based on coronary angiography: 27 without LAD stenosis and 15 with LAD stenosis (>50%).
- Pulsed tissue Doppler echocardiography of the interventricular septum and mitral annulus was performed.
Main Results:
- Patients with LAD stenosis exhibited lower septal systolic myocardial (Sm) and atrial peak velocities, increased PSM, and prolonged relaxation and pre-contraction times.
- A septal Sm/PSM ratio < 1 had 73% sensitivity and 77% specificity for detecting LAD stenosis.
- LAD stenosis and ejection fraction were independent predictors of PSM.
Conclusions:
- Pulsed tissue Doppler can identify distinct septal myocardial asynchrony patterns in LBBB patients.
- Tissue Doppler imaging may aid in distinguishing LBBB with versus without LAD stenosis based on PSM characteristics.
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.
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