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[Left bundle-branch block: inferences from ventricular septal motion in the echocardiogram concerning left
Insights
In left bundle branch block (LBBB), distinct interventricular septum (IVS) motions identified via M-mode echocardiography correlate with disease severity. Paradoxical IVS motion indicates a more advanced clinical stage and poorer outcomes.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Context:
- Left bundle branch block (LBBB) is associated with abnormal interventricular septum (IVS) motion.
- M-mode echocardiography is a key diagnostic tool for assessing cardiac function.
Purpose:
- To determine if distinct patterns of IVS motion in LBBB patients can be identified using M-mode echocardiography.
- To investigate the correlation between these IVS motion patterns and clinical data.
Summary:
- Analyzed M-mode echocardiograms of 100 LBBB patients, identifying three IVS motion types: anterior (paradoxical, Type A), posterior (normal, Type B), and intermediate (Type AB).
- Type A (18%) showed more severe disease, longer QRS duration, larger cardiac-thoracic ratio, and larger left ventricular end-diastolic diameters compared to Type B (58%).
- Type A also had lower ejection fraction and higher mean pulmonary artery pressure, with 88% of Types A and AB exhibiting abnormal pulmonary artery pressure.
Impact:
- M-mode echocardiography can differentiate IVS motion patterns in LBBB, offering prognostic information.
- These patterns correlate with disease severity, ventricular function, and pulmonary artery pressures.
- Findings aid in risk stratification and management of LBBB patients.
Abstract:
In left bundle branch block (LBBB) abnormal motions of the interventricular septum (IVS) are well known in echocardiography. We asked: (1) Is it possible to distinguish several kinds of IVS motion in the M-mode echocardiogram and (2) Is there any correlation with clinical data? We analyzed the M-mode echocardiograms of 100 patients in whom LBBB had been diagnosed, either alone or in connection with latent or dilatative cardiomyopathy. All showed a posterior motion of the IVS in early systole. Three kinds of motion could subsequently be identified: anterior (= paradox) (18%, type A), posterior (= normal) (58%, type B), and intermediate (24%, type AB). Group A had a more severe clinical stage of disease than group B (p less than 0.0005); ECG showed a longer QRS complex (p less than 0.0005), X-ray a bigger cardiac-thoracic ratio (p less than 0.0005), and M-mode-echocardiogram larger left ventricular end-diastolic diameters (p less than 0.025). Mean values of group AB fell between those of group A and those of group B. Moreover, ejection fraction at left ventricular angiography was lower in group A (52.0%) than in groups AB (58.0%) and B (62.9%) (A vs B p less than 0.005), and mean pulmonary artery pressure on exertion was higher in group A (43.3 mm Hg) than in groups AB (38.1 mm Hg) and B (28.7 mm Hg) (A vs. B p less than 0.0005). For types A and AB taken together, the likelihood of abnormal pulmonary artery pressure on exertion was 88%.(ABSTRACT TRUNCATED AT 250 WORDS)