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Left bundle branch block: angiographic segmental wall motion abnormalities
Insights
Left bundle branch block (LBBB) can cause abnormal ventricular wall motion, even without heart disease. This study found regional wall motion abnormalities in most LBBB patients, suggesting activation sequence as a cause.
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Diagnostic Imaging
Background:
- Previous studies using contrast ventriculography reported normal ventricular wall motion in left bundle branch block (LBBB) patients without coronary artery disease or cardiomyopathy.
- Recent echocardiographic studies suggest a high prevalence of septal wall asynergy in LBBB patients.
Purpose of the Study:
- To investigate left ventricular (LV) wall motion in patients with LBBB and no significant coronary artery disease or diffuse cardiomyopathy.
- To compare LV wall motion between LBBB patients and controls with normal intraventricular conduction.
Main Methods:
- Analysis of biplane cineangiograms from 15 LBBB patients and 100 controls.
- Utilized both qualitative visual inspection and computer-assisted quantitative methods for wall motion assessment.
- Compared wall motion along defined hemiaxes.
Main Results:
- Qualitative review revealed regional akinesia or dyskinesia in 6 of 15 LBBB patients versus none of 100 controls (P < 0.001).
- Quantitative review showed abnormal wall motion in 10 of 12 LBBB patients along at least one hemiaxis.
- Significant difference in regional wall motion abnormalities between LBBB patients and controls.
Conclusions:
- Angiographic regional wall motion abnormalities are common in LBBB patients, irrespective of coronary artery disease or cardiomyopathy.
- Abnormalities may stem from the altered sequence of ventricular activation, not necessarily myocardial fibrosis.
Abstract:
Ventricular wall motion as studied with contrast ventriculography has been judged normal in the few previously reported cases of patients with left bundle branch block who have neither coronary artery disease nor diffuse cardiomyopathy. However, recent echocardiographic studies have demonstrated a high frequency of segmental asynergy of the septal wall in such patients. In this study left ventricular wall motion was analyzed in 15 patients with left bundle branch block and without significant coronary artery disease or diffuse cardiomyopathy. Biplane cineangiograms from these patients were compared with those from 100 consecutive patients with normal intraventricular conduction and without coronary artery disease or cardiomyopathy using two techniques: qualitative visual inspection and a computer-assisted quantitative method. By qualitative review, 6 of 15 patients with left bundle branch block had regional akinesia or dyskinesia as compared with none of 100 patients with normal intraventricular conduction (chi square = 42.3; P less than 0.001). By quantitative review, 10 of 12 patients with left bundle branch block had abnormal wall motion along at least one hemiaxis. It is concluded that angiographic regional wall motion abnormalities are common in patients with left bundle branch block, even in the absence of coronary artery disease or diffuse cardiomyopathy. The abnormalities may result from the abnormal sequence of ventricular activation rather than from myocardial fibrosis.