|Year : 2020 | Volume
| Issue : 3 | Page : 128-133
Angiographic pattern of patients with left bundle branch block: A comparative cross-sectional study
Islam Elsayed Shehata1, Ahmed Abdel-Aziz Mohamed2, Tarek Ahmed Naguib1, Amroo Abdul-Monem Ateya1, Ahmed Saeid Eldamanhory1
1 Department of Cardiology, Faculty of Medicine, Zagazig University, Zagazig, Egypt
2 Department of Cardiology, Banha Teaching Hospital, Banha, Egypt
|Date of Submission||21-Jul-2020|
|Date of Decision||30-Aug-2020|
|Date of Acceptance||21-Sep-2020|
|Date of Web Publication||23-Dec-2020|
Dr. Islam Elsayed Shehata
Department of Cardiology, Faculty of Medicine, Zagazig University, Zagazig 44519
Source of Support: None, Conflict of Interest: None
Objectives: We purposed to determine the relationship between left bundle branch block (LBBB) and coronary artery disease (CAD) site, severity, and CAD risk factors. Methods: Eighty patients with LBBB were sorted into two groups based on coronary angiography (CA) findings: Group 1: 56 patients with CAD (stenosis ≥70% in ≥1 epicardial vessel) and Group 2: 24 patients with normal coronaries. Results: Our observations confirm male preponderance of LBBB and affirm hypertension and diabetes as common risk factors for CAD within this subpopulation. Hence, these risk factors can be considered a strong predictor of CAD in LBBB. Cardiac echocardiography data suggest that LBBB and CAD are associated with regional hypokinesia and decreased ejection fraction. The most frequently diseased vessel was left anterior descending (LAD), followed by left circumflex then right coronary artery. Our study CA showed single-vessel disease (SVD) in 37 participants (46.3%), two-vessel disease in 16 subjects (20%), three-vessel disease in 3 subjects (3.8%), and normal vessels in 24 participants (30%). Hence, SVD frequency was high in our study. Conclusion: The risk for left ventricular dysfunction and SVD more commonly LAD artery involvement had increased in the presence of LBBB in electrocardiogram. CA present only in tertiary centers, which considered a major and invasive diagnostic tool for CAD, so selection criteria are required to predict patients with LBBB who are prone to be at risk of CAD and need this invasive procedure, on the other hand, avoid CAD overdiagnosis, unnecessary admissions to hospital, and antianginal drugs consumption.
Keywords: Coronary angiography, coronary artery disease, ischemic heart disease, left bundle branch block, left ventricular dysfunction
|How to cite this article:|
Shehata IE, Mohamed AA, Naguib TA, Ateya AA, Eldamanhory AS. Angiographic pattern of patients with left bundle branch block: A comparative cross-sectional study. J Indian coll cardiol 2020;10:128-33
|How to cite this URL:|
Shehata IE, Mohamed AA, Naguib TA, Ateya AA, Eldamanhory AS. Angiographic pattern of patients with left bundle branch block: A comparative cross-sectional study. J Indian coll cardiol [serial online] 2020 [cited 2021 Sep 18];10:128-33. Available from: https://www.joicc.org/text.asp?2020/10/3/128/304378
| Introduction|| |
Left bundle branch block (LBBB) has a recognized bad outcome and is associated with coronary artery disease (CAD), hypertension, idiopathic dilated cardiomyopathy, degenerative disease of the conductive system, and aortic stenosis.
Coronary angiography (CA) remains the clinical gold standard for the diagnosis of CAD.
The noninvasive diagnosis of CAD was difficult in the presence of complete LBBB, so those participants often are referred for CA to assess the presence and severity of CAD. Hence, we purposed to detect the relationship between complete LBBB, CAD site, severity, and CAD risk factors.
| Methods|| |
This comparative cross-section study was conducted at our cardiology department during the period from November 2013 to October 2014 on eighty patients with LBBB, 52 males (65%) and 28 females (35%) with their age ranged from 39 to 77 years and divided according to CA findings into two groups: Group I: 56 participants (37 males and 19 females) with significant CAD (diameter of stenosis ≥70%in ≥1 epicardial vessel) and Group II: 24 controls (15 males and 9 females) with normal coronaries.
Thorough history taking and full clinical examination done to all participants as well as resting 12-lead standard electrocardiogram (ECG), laboratory analysis, chest X-ray (CXR), echocardiography (Echo), and coronary angiography (CA). The protocol was approved by our Zagazig University Institutional Review Board (ZU-IRB), which confirmed that all methods were performed in accordance with the relevant guidelines and regulations, and informed consent was obtained from all participants.
Patients with LBBB whom had done coronary angiography.
Patients with non-LBBB, CAD, LBBB with previous percutaneous coronary intervention, or coronary artery bypass grafting, and patients contraindicated for CA (heart failure, renal failure, and liver cell failure) were excluded from the study.
Type of study
This was a comparative cross-sectional study.
Steps of performance and techniques used
Complete history taking
Complete history taking includes age, sex, and special interest to determine risk factors for CAD as hypertension, diabetes mellitus, smoking, dyslipidemia, obesity, stress, and positive family history for ischemic disease.
General and local examination
- General features including patient's appearance, decubitus, complexion, temperature, respiratory rate, oxygen saturation, blood pressure, pulse (rate, rhythm, force, equally, volume, and character of pulse), the presence of basal rales, and jugular venous pressure election
- Local examination of the heart for cardiomegaly, pulsations, thrills, heart sounds, and murmurs.
according to the American Heart Association/European Society of Cardiology guidelines, LBBB can be defined as: [Figure 1]
|Figure 1: Electrocardiogram of coronary artery disease patient with left bundle branch block|
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- QRS duration ≥120 ms in adults, >100 ms in children 4–16 years of age, and >90 ms in children <4 years of age
- Broad notched or slurred R wave in leads I, aVL, V5, and V6 and an occasional RS pattern in V5 and V6 attributed to displaced transition of QRS complex
- 3-Absent q waves in leads I, V5, and V6, but in the lead aVL, a narrow q wave may be present in the absence of myocardial pathology
- R peak time >60 ms in leads V5 and V6 but normal in leads V1, V2, and V3, when small initial r waves can be discerned in the above leads
- ST and T waves usually opposite in direction to QRS
- Positive T wave in leads with upright QRS may be normal (positive concordance)
- Depressed ST segment and/or negative T wave in leads with negative QRS (negative concordance) are abnormal
- The appearance of LBBB may change the mean QRS axis in the frontal plane to the right, to the left, or to a superior, in some cases in a rate-dependent manner.
Transthoracic echocardiography-Doppler evaluation
All participants will undergo two dimensional and Doppler Echo according to the recommendations of the American Society of Echocardiography (ASE) during hospitalization and after 1 month of presentation to assess the following parameters: [Figure 2].
|Figure 2: Transthoracic echocardiography measurement of left ventricular ejection fraction by M- mode|
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- Left ventricular dimensions will be measured with conventional M-mode from parasternal short-axis view using a leading edge to edge at the level of the papillary muscles
- These measurements include
- left ventricular end-diastolic diameter
- left ventricular end-systolic diameter
- Posterior wall thickness
- Interventicular septal thickness
- Assessment of segmental wall motion at rest
- Doppler flow at mitral valve will be recorded for the assessment of E/A ratio
- Detecting the degree of mitral regurgitation, tricuspid regurgitation, and measuring right ventricular systolic pressure.
All participates underwent control CA [Figure 3]. Standard angiographic views were obtained and digitally stored to reveal the presence or absence of CAD and its severity if present and site of the lesion.
|Figure 3: Coronary angiography shows left anterior descending significant lesion|
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All data were analyzed using SPSS software statistical package for social science version 22 (SPSS, Inc. Chicago, IL, USA).
Qualitative data are presented as number and percent, and Chi-square test is used for comparison between groups.
Quantitative data are summarized as a mean and standard deviation which the comparison of two mean was done by independent t-test.
| Results|| |
The clinical and demographic characteristics
In our study, both groups were comparable as regards demographic and clinical characteristics; males were more common in both groups. The risk factors of CAD were more in Group I than in Group II [Table 1].
In our study:
- LBBB was more common in hypertensive old diabetic patients
- LBBB was significantly associated with a significant coronary lesion in hypertensive old diabetics, so these risk factors can be considered a strong predictor of CAD in LBBB.
In our study, we detected CAD in 56 (70%) patients and left ventricular systolic dysfunction (LVSD) in 48 (60%) patients. Hypertension found in 38 (47.5%) and diabetes mellitus (DM) in 31 (38.8%) patients; DM and LVSD were more associated with significant CAD [Table 2] and [Table 3].
|Table 3: Comparative studies between both groups regarding to ejection fraction|
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Coronary angiography data
In our study, we detected right coronary artery (RCA) lesions in 14 patients (17.5%), left circumflex (LCX) artery lesions in 15 patients (18.8%), and left anterior descending (LAD) artery lesion in 49 patients (61.3%) and so: [Figure 4] and [Table 4].
|Table 4: The location of significant coronary artery disease in left bundle branch block patients|
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- The most common diseased vessel was LAD, followed by LCX and RCA.
In our study, CA detected single-vessel disease (SVD) in 37 participants (46.2%), two-vessel disease (2VD) in 16 participants (20%), three-vessel disease (3VD) in 3 participants (3.8%), and normal vessels in 24 participants (30%) So:
- SVD was common in our study
- There was no left main coronary artery (LMCA) involvement in our study, and so we did not support the hypothesis that the severity of CAD (in terms of LMCA, involvement, or 3VD) can be predicted by the presence of LBBB with CAD. Side effects were low and temporary, no major complications in the form of myocardial infarction, serious cardiac arrhythmias, or cardiac death have occurred.
| Discussion|| |
Demographic and clinical characteristics of the studied patients
In our study, LBBB was common among old age groups; the incidence was 50% at age 40 years, 66% at age of age 60 years, and 77.4% at age more than 60 years, the mean age of the study was 57.59 ± 7.64 years which was close to that illustrated by Eriksson et al. in a prospective study of 855 Swedish men in the general population who were 50 years of age and followed for 30 years: the incidence was 0.4% in at age of 50, 2.3% at age of 75, and 5.7% at age of 80. LBBB is infrequent in young healthy participants. As an example, a study of 237,000 airmen under age 30 found only 125 cases of LBBB, representing an incidence of 0.05%. Ninety per cent of these participants had no apparent heart disease. The prognosis of isolated LBBB in young men is generally benign.
Regarding gender, LBBB was more common in males than females as 52 patients (65%) of the overall eighty patients were males, there was more male predominance (66.1%) and mean age (59.02 ± 7.14 years) in Group I (with CAD) than Group II (without CAD), there were significant differences regarding age, and no significant difference regarding gender between both groups. This is in agreement with several studies which showed that males are more prone to CAD.
Our patients had a history of hypertension, diabetes mellitus, dyslipidemia, current smoking, and family history as risk factors; these risk factors were assessed to find out the strength of association between the studied risk factors with the presence of a coronary lesion.
Risk factors in studied groups
Concerning risk factors, hypertension was the most common risk factor present in LBBB patients 38 out of 80 (47.5%).
The incidence of these risk factors was found to be higher in Group I (with CAD) than in Group II (without CAD); there were significant differences regarding hypertension and diabetes mellitus between both groups. These were in agreement with several studies which had proposed that CAD risk factors include hypertension, diabetes mellitus done by Barrett-Connor et al., and family history and smoking done by Messner and Bernhard.
In the current study, 33 out of 38 patients were hypertensive and having significant CAD (86.8%), and 27 out of 31 patients were diabetic and having significant CAD (87.1%), as found in a comparable study done by Alwan and Yousif.
Patients with diabetes and LBBB were associated with increased severity of CAD and more risk for 3VD.
In the current study, 21 out of 26 were dyslipidemic and having significant CAD (80.8%) without significant difference between Group I and Group II.
Regarding smoking, 21 patients out of 30 were smoker and having significant CAD (70%) without significant difference between Group I and Group II.
Comparative study between both groups regarding ejection fraction
In the current study, LBBB is associated with echocardiographic evidence of depressed ejection fraction (EF < 50%), 51 patients out of 80 had depressed EF (63.8%). On the other hand, patients with significant CAD (Group I) were more associated with LVSD than in normal coronaries and 28 patients had depressed EF and significant CAD out of 51 (54.9%) patients. Old age groups were associated with LVSD in contrary to the younger patients, which may be explained by occurrences of critical coronary stenosis among old patients as found in this study, and this can be explained by an increased in the risk factors among the olds as HTN and DM. Risk factors were assessed to find out the strength of association between the studied risk factors with the presence of coronary lesion, although hypertension was the most common risk factor present in CAD with LBBB (86.8%) but was the least to be associated with significant coronary narrowing, this might be because HTN itself may be the cause of LBBB as it is a well-known cause of LBBB; however, DM was more strongly associated with coronary lesion (63.6%) as found in a comparable study, as well as found by Ozeke et al. as they prospectively analyzed data of 51 patients with Type 2 DM with LBBB, 51 patients with Type 2 diabetes mellitus without LBBB, and 51 patients with isolated LBBB matched for age and gender. Patients with diabetes and LBBB associated with increased severity of CAD and more risk for 3VD.
Comparative study between both groups regarding site of wall motion abnormality [Table 2]
Regarding regional wall motion abnormality, hypokinesia was a prominent finding detected by echo in patients with LBBB; we found that septal hypokinesia present in 45 (56.3%) patients, anterior hypokinesia in 39 (48.8%) patients, apical hypokinesia present in 37 (46.3%) patients, inferior hypokinesia present in 19 (23.8%) patients, and lateral hypokinesia present in 16 (20%) patients.
Patients with significant CAD (Group I) were more associated with regional wall motion abnormality than in Group II, 35 patients had a significant CAD and anterior hypokinesia (62.5%), 15 patients had significant CAD and inferior hypokinesia (26.8%), 13 patients had significant CAD and lateral hypokinesia (23.2%), 33 patients had significant CAD and apical hypokinesia (58.9%), and forty patients had significant CAD and septal hypokinesia (71.4%); there was positive relationship regarding septal, apical, and anterior hypokinesia (P < 0.001) between both studied groups, this is comparable with other studies showed that patients with LBBB and significant CAD had echocardiographic evidence of regional wall motion abnormality and or depressed EF.
Angiographic pattern in studied groups
In the current study, 56 patients (70%) of the overall eighty patients indicate underlying significant CAD. This is in agreement with several studies as in a study conducted by Lashari et al., in which the prevalence was 84%. Other studies as Framingham study, 45% of patients with LBBB were reported to have CAD.
In the current study group of 56 patients diagnosed with significant coronary heart disease, CA showed that 49 patients (61.3%) had LAD disease, 15 patients (18.8%) had LCX disease, and 14 patients (17.5%) had right CAD, so the most common diseased vessel was LAD, followed by LCX and RCA. This is in agreement with Merić et al.,, who had demonstrated that CAD was the most frequent cause of LBBB and most frequently was LAD stenosis. This can be explained by septal branches of LAD thought to be main blood supplier to left conductive tissues, although in patients with normal coronaries, the defected tissue is due to global degenerative disorder that affects the whole heart.
In our study, LMCA was not involved compared to the study done by Nishtar et al. LMCA was involved only in 3.36% of patients.
Percentage of diseased vessels in both groups
Regarding the number of vessels involved in patients with CAD, the current study showed that SVD was the most common finding in CAD with LBBB; 37 patients had SVD out of 56 patients with significant CAD (66.1%) and represent 46.2% of patients with LBBB, 16 patients had 2VD out of 56 patients with significant CAD (28.5%) and represent 20% of patients of LBBB, 3 patients had 3VD out of 56 patients with significant CAD (5.3%) and represent 3.8% of patients with LBBB, concerning this, the studies are controversial, Lashari et al. showed in their study that SVD, 2VD, and 3VD was present in 23%, 24%, and 37%, respectively.
In our study, 24 patients out of 80 patients with LBBB had normal angiography or insignificant CAD (30%).
Limitations of the study
Further work is needed on a wide scale of participants to support and evaluate the results of this study, since the number of cases in the present study was limited.
CA present only in tertiary centers which considered a major and invasive diagnostic tool for CAD, so selection criteria are required to predict patients with LBBB who are prone to be at risk of CAD and need this invasive procedure, on the other hand avoid CAD overdiagnosis, unnecessary admissions to hospital, and antianginal drugs consumption.
| Conclusion|| |
The risk for left ventricular dysfunction and SVD more commonly LAD involvement has increased in the presence of LBBB in ECG; therefore, we recommend that:
- CA should be done in patients with LBBB who have ischemic chest pain or who have risk factors for CAD
- For accurate diagnosis of obstructive CAD in patients with LBBB, CA is should be done to confirm or roll out obstructive CAD.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]