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Updated: Apr 18, 2026
Evaluation of Left Ventricular Structure and Function using 3D Echocardiography
Published on: October 28, 2020
Relationship between electrocardiographic characteristics of left bundle branch block and echocardiographic findings
Augusto J Lépori, Ricardo S Mishima, Gonzalo Rodriguez
1FACC Sanatorio Allende. eddie.moreyra@gmail.com.
Insights
Complete left bundle branch block (CLBBB) often indicates underlying structural heart disease, complicating ECG diagnoses of left ventricular hypertrophy and myocardial infarction. No ECG findings reliably identified patients with structural heart disease.
Area of Science:
- Cardiology
- Electrocardiography
- Cardiac Imaging
Background:
- Complete left bundle branch block (CLBBB) is an electrocardiographic finding associated with structural heart disease and poor prognosis.
- CLBBB complicates the interpretation of standard ECG criteria for left ventricular hypertrophy (LVH), chronic myocardial infarction (MI), and ST-T wave abnormalities.
Purpose of the Study:
- To investigate the relationship between CLBBB and cardiac structural abnormalities detected by echocardiography.
Main Methods:
- Observational, cross-sectional study.
- Included 101 patients with CLBBB on ECG.
- Transthoracic echocardiogram (TTE) performed within 6 months of ECG.
Main Results:
- 90% of patients exhibited structural heart disease on TTE.
- No ECG criteria effectively diagnosed LVH; no correlation found between ECG signs and increased left ventricular mass index.
- QRS duration and left axis deviation were not associated with reduced left ventricular ejection fraction (LVEF).
- ECG criteria for chronic MI showed high specificity but low sensitivity.
Conclusions:
- CLBBB is linked to a high prevalence of cardiac structural disease.
- CLBBB impedes ECG diagnosis of LVH, reduced LVEF, and chronic MI.
- No ECG finding differentiated patients with or without structural heart disease; chronic MI criteria are useful but not definitive when absent.
Background:
Complete left bundle branch block (CLBBB) is an electrocardiographic (ECG) dromotropic disorder seen in patients with various structural heart diseases and sometimes is associated with poor prognosis. Its presence confounds the application of standard ECG criteria for the diagnosis of left ventricular hypertrophy (LVH), myocardial infarction (MI) in the chronic phase, and pathologies that produce changes on ST-T segment. The aim of this investigation was to establish the relationship between CLBBB and cardiac structural abnormalities assessed by echocardiography.
Methods:
This observational, cross-sectional study included ECG with CLBBB from 101 patients who also had transthoracic echocardiogram (TTE) performed within 6 months.
Results:
The prevalence of structural heart disease on TTE was 90%. No ECG criterion was useful to diagnose LVH since no relationship was observed between 9 different ECG signs and increased left ventricular mass index. QRS duration (p = 0.16) and left axis deviation (p = 0.09) were unrelated to reduced left ventricular ejection fraction (LVEF). Eight ECG signs proposed for the diagnosis of the chronic phase of MI demonstrated similar effectiveness, with high specificity and reduced sensitivity.
Conclusions:
CLBBB is associated with elevated prevalence of cardiac structural disease and hinders the application of common ECG criteria for the diagnosis of LVH, reduced LVEF, or chronic phase of MI. No ECG finding distinguished patients with structural heart disease from those with normal hearts. Electrocardiographic criteria for the diagnosis of MI in the chronic phase are useful when present, but when absent cannot rule it out.
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